Handbook for Clerks of WorksThird edition

Greater London CouncilDepartment of Architectureand Civic Design

The Architectural Press l London

First published by the Greater London Council July 1973Reprinted September 1973 and March 1974Second edition published by The Architectural Press Ltd1979Third edition published by The Architectural Press Ltd 1983Reprinted 1987The Handbook was originally compiled by E. T. Dean,formerly the Greater London Council Sites Manager0 Greater London Council 1973, 1979 and 1983British Library Cataloguing in Publication DataGreater London Council. Department of Architecture

and Civic DesignHandbook for Clerks of Works.-2nd ed.1. Building-England-London-Superintendence2. Greater London Council. Department of Architectureand Civic Design-Officials and employeesI. Title6 2 4 TH438ISBN 0-851 39-853-7

All rights reserved. No part of this publication maybe reproduced, stored in a retrieval system, ortransmitted, in any form or by any means, electronic,mechanical, photocopying, recording or otherwise, withoutthe prior permission of the publishers. Such permission,if granted, is subject to a fee depending on the natureof the usePrinted and bound in Great Britain byBiddles Ltd, Guildford and King’s Lynn

Contents

1 Duties andresponsibilities of aClerk of Works

1 Generally 12 Definition of duties 13 Effect of Clause 10 24 Definition of Clerk of Works duties in issue of

instructions 25 Contractor’s attitudes 26 Specific limitations to Clerk of Works duties 37 Variety of duties of a Clerk of Works

38 Knowledge of Contract Documents3

9 Building Regulations and Acts 410 Cooperative relations with Agent11 Anticipation

4

12 Interpretation4

13 Inspection5

14 Reporting5

15 Recording and the Job Diary5

16 Diary I tems1 7 I s s u e o f D i a r y

5

618 Query and Answer Book

5

19 Weekly Report-General Remarks 6

20 Percentage completion figures for Housing7

21 Safety7

22 Labour disputes77

2 Commencement of acontract

3 Site levels andboundaries

4 Contract documents

1 Briefing Meetings 92 Handing-over of site 93 Sit ing of off ices 94 Telephone 95 Datum points for setting out and levelling 96 T r e e s 107 Contractor’s name boards 108 Council notice boards 109 Bulk supplies 10

10 Existing services 1011 Levels over s i te 1012 Pavements 11

1 Surface levels of site 122 Fly tipping 12

3 Agreement and recording of surface levels 12

4 Leve l Book 13

5 Datum for levels 13

6 Adjoining property 137 Damage to property 138 Adjoining contracts 139 Completed services 13

10 Si te boundar ies 1411 Street l ighting 1412 Temporary fencing owned by the Counci l 14

1 F o r m o f c o n t r a c t 15

2 Contract drawings 15

V

5 Progress of works

8 Marking up progress charts 2 19 Routine records of progress matters 21

10 Progress difficulties 2 211 Errors involv ing loss of t ime 2 2

6 Instructions tocontractors

7 Site investigations

8 Foundations

3 Clerk of Works in the form of contract 164 Matters on which the architect is empowered to

issue instructions 165 Confirmations within two working days 166 Timely supply of information 167 Extension of time of completion 178 Stoppages 17

9 Nominated sub-contractors and suppliers 1710 Care of drawings 1811 Amendments to drawings and documents12 Index to specification or contract bills

18

13 Return of documents1 8

14 Completion certificates181 8

1 Responsibil i ty of Clerk of Works for progress 1 92 Weekly repor t - to char t progress of the works

and factors that affect that progress 1 93 R e c o r d s o f l a b o u r

2 04 Record of s toppages

2 0

5 Potent ia l causes of delay2 0

6 Progress charts 2 07 Site Meetings 2 1

1 Additional works 2 32 S i te ins t ruc t ions by Clerk o f Works 2 33 Dayworks 2 44 Contractor’s Vouchers5 Contractor’s paysheets

2 42 4

6 Instruction to correct defective work 2 5

1 General 262 First investigation of a site 2 63 Soi ls invest igat ion by specia l is t f i rms 264 Pr imary purpose of term contracts 2 75 Other Soi ls Engineer ing problems 276 Chemical Analyses 2 77 Co-ord inat ion of Theory and Pract ice 2 78 S p a c i n g o f t r i a l b o r e s 2 79 Sub-so i l soundings 2 7

1 0 C o d e o f P r a c t i c e 2 8

1 Setting out foundations 292 Bottoms of excavations 293 Excavation beyond contract depth 29

vi

9 Drainage

10 Concrete andreinforced concrete

4 Visits of Structural Engineers to sites 305 Concreting foundations 306 Records of foundations 3 07 Physical start to individual blocks 31

8 Records of obstructions 319 Piled foundations 3 1

10 Water in excavated foundations 3 211 Extent of excavations 3212 Safety in excavations 3213 Objects of antiquity 3214 Cultivation of areas to be planted or grassed 3315 Information 3 3

1 Checking levels and locations of existing sewers 352 Setting out 353 Excavations 354 Support and protection of the proposed sewers

and drains 355 Back-filling 3 66 Timber left in 367 T e s t i n g o f s e w e r a n d d r a i n s 368 Connection to existing sewers 369 Handing over of sewers and drains 36

1 Code of Practice 110 3 72 Developments 3 73 Types of concrete 3 74 Definit ions 3 7

5 Demonstrat ion that designed mix achieves theappropriate surface finish 3 8

6 G r a d e s o f c o n c r e t e 3 87 T h e L o n d o n B u i l d i n g A c t8 Departmental Preambles

3 8

9 Proportioning Materials on site

3 8

10 Frequent test cubes11 Calc ium chlor ide in concrete

3 8

12 Change in mater ia ls

3 9

13 Competent supervision by Contractor

3 9

14 Ready mixed concrete-choice of depot15 Minimum cement content-Ready Mixed

39

Conc re te

3 9

16 Careful check of Ready Mixed Concrete by

4 0

4 0

Clerk of Works

4 0

4 017 Check of delivery times-Ready Mixed Concrete 4 018 Disclosure of additives 4 019 Mixing concrete on site

4 120 Materials for concreting on site4 121 Marine aggregates4 122 Gauge Boxes4 123 Mixer size4 124 Formwork4 225 Cleaning out formwork

vii

11 Brickwork 26 Plac ing of concrete 4 227 Construction joints 4 228 Concret ing in cold weather

4 329 Compaction of concrete43

4 330 Curing and protection4 431 H igh a l um ina cemen t

4 532 Reinforcement 4 53 3 P r o v i s i o n f o r p i p e s

4 53 4 S t r i k i n g o f f o r m w o r k

4 635 Damaged or defect ive work in general 4 6

4 636 Specif ied surface f inishes

47

37 Colour38 Vertical alignment and setting out in multi-

storey reinforced concrete work39 Clerk of Works to seek instructions on accuracy

48measurements that are to be taken40 Designed mixes-Field Control Samples and

48Test cubes41 Nominal or prescribed mixes-Field Control 49

Samples and test cubes42 B.S. references for sampling, slump and cubes 49

43 Covermeter checks 49

1 S e t t i n g o u t o f b r i c k w o r k 502 Datum for brickwork 503 D a m p p r o o f c o u r s e s 504 Points for a t tent ion in br ickwork 505 Particular attention to cavity brickwork

516 W e e p h o l e s

51

7 C losu re o f cav i t y51

8 S n a p h e a d e r s 519 Mor ta r m ix i ng 51

10 Point ing 5211 Sample br ick panels 521 2 S a m p l e l o a d s o f b r i c k s 5213 Br ickwork in f rosty weather 5214 Admixtures 5215 Examinat ion of br ickwork bui l t in f rost16 Si l ls and thresholds 5317 Par t i t ion b locks

53

18 Tests dur ing br ickwork53

1 9 F l u e s20 Making good to ducts and other party structures

53

21 Records that are to be kept of all cavity and

53

54simi lar br ickwork

54

5422 Manner in which records are to be kept5423 Cladding panels

5424 Cracking of brickwork and failures of brick-

55c l a d d i n g

25 Code of Practice C.P. 121

12 Stretss grading of timber 1 Code of Practice C.P. 112 57

Viii

13 Joinery 123456789

1 01 11 21 31 41 51 61 71 81 92 02 12 22 32 42 52 62 72 82 9

2 Stress Grading 573 Methods of grading 574 Limitations of Machine stress grading 575 Colour coding in machine grading 58

14 Mastic asphalt roofing 12345678

91011

121314

T i m b e r 59Timber windows 59Quality of timber 59Early decay of timber 59Early occurrence of wet rot 59Mo i s tu re 59

Sapwood in softwood 59

Sapwood in hardwood 60

Measures to be taken with softwood in present-day use 60Preservation 60Moisture content of joinery as delivered on site 61Maintenance of low moisture content 61Special steps for centrally heated buildings 61Moisture danger limit 61Examination of joinery drawings and specification 61Sample items of joinery 6 2Visits to joinery works 6 2Rules for visits to works 6 3Guidance notes on joinery inspections 6 3Earlier specifications 6 6Windows for breakdown examination 6 6Window test rigs 6 6The combed joint 6 6Glues 67Notes on priming 67Hardwood flooring on screeds 67Preservation-wooden doors to garages 67Skirtings 6 7Paint protection of putties 67

Information necessary to all Clerks of WorksDefinition of Mastic AsphaltBRS check on asphalt roofsSuccessful use of Mastic AsphaltAppropriate inspection by Clerk of WorksTypical faultsReflective treatmentsA small working gang and its Tools andE q u i p m e n tTypical Working OperationsThe underlayOverall thickness of asphalt and numberof coatsTemporary applications of asphaltDeta i l ingImprovements to certain details

7 17 17 17 17 27 27 3

7 3747 4

75757676

ix

15 Plastering

16 Decoration

18

17 Protection of finishedwork and protection instorage

Completed buildings-handing over

1 Trueness of the plastering system 772 Thin coat 773 1 in 600 tolerance 774 Quality of workmanship in plastering 775 Sample dwellings 786 Preparation of background for plastering

787 Excessive making good of plaster

78

8 Cleanliness in plastering78

9 Mixes for plastering 78

1 0 Detailed inspection of plaster work 78

1 1 Sound insulating quilt 79

1 2 Screed for Thermoplastic tiles 79

13 Protection from weather 791 4 Temporary lighting 791 5 P a t c h i n g 791 6 Bonding agents 7917 Preference for Mechanical Key 80

1 Inspect ion-general 812 Quality of finished work 813 Preparation 814 Dry surfaces 815 Faulty materials 826 Number of coats of paint 827 Cleanliness of finished paint work 828 Delivery of paint 829 Dilution of paints-general 82

1 0 Primers for joinery 821 1 Brushes for priming joinery 8312 Paint tests 8313 Paint sampling 831 4 Excessive thinning of paints 841 5 Instant paint testing 841 6 List of approved brands 84

1 General Protection 852 Orderliness of site 8 53 W aste of materials 8 54 Stonework and precast work 8 55 Protection of new brickwork 856 Protective measures for concrete 867 Protection in storage 868 Storage of sanitary goods 8 69 Plumbing-Frost precautions 8 6

10 Storage of metal windows 8 61 1 Handling of baths 8 61 2 General storage and stacking of baths 8 6

1 Use of permanent lifts 882 Use of electrical wiring 883 Minimum defects at final handover 884 Systematic clearance of defects 88

x

19 Sub-contractors

567

89

10

111213141516171819

Preliminary official inspectionFormal handing over inspectionFormal notification to contractor of defectsfrom formal handing over inspectionDilatoriness in remedying defectsTroublesome ‘Snagging’ ListsTimely steps and pressure to clear up thefinal few defectsClerk of Works clearance certificateReports on completionsTransformer chambersMaintenance surveysRecovery of Council fencing materialsHorizontal centre pivot windowsStop cocksTesting of gas installationCradling eye bolts

1 Instructions to sub-contractors 932 Approval of sub-contractors 933 Nominated sub-contractors 934 Direct Contractors 935 Direct Supplies 936 Work by outside authorities 947 Work by outside specialists 948 Labour-only sub-contractor 94

20 Materials 123456789

101112131415

Material approvals 95Major deliveries 95Sources of materials 95Deliveries of joinery 95Direct supply-Procedure 96Direct supply-Requisitioning 96Direct supply-Deliveries 96Direct supply-Quality 96Direct supply-Replacement 97Direct supply-Delivery delays 97Name plates 97Standardisation of direct supply materials 97Damage to baths 97Prevention of impact damage 98Pads for feet of baths 98

21 Testing 1 General policy on testing2 Site testing equipment3 Laboratories at County Hall4 Testing of Mastic Asphalt-Outside

Laboratories5 Forms to accompany samples6 Supervision of sampling7 Clerk of Works records8 Tests on site

8889

898990

90909090909191919191

999999

99100100100101

x i

9

10111213141516171819202122

22 lndustrialised Buildings 12345

23 Training and the Supply 1of Technical Information 2to Clerks of Works

3

4

5

6

7

89

101 1

24 Relations with other 1departments and 2branches 3

456

7

89

General Co-ordinationStructural EngineerHousing EngineerQuantity SurveyorDistrict SurveyorRelationships between District Surveyorand Clerk of WorksMutual confidence between Clerk of Worksand District SurveyorAesthetic considerationsEnvironmental Health Officer

Samples sent from the site by Clerksof Works for testsTesting scheduleExamination of sandMarine aggregatesSlump testsField weight tests on lightweight screedsGeneral remarks on drainage testingPile tests noteGeneral remarks on paint testingTests on fluesTesting of bricksTesting of slatesCement testingTesting of reinforcement

GenerallndustrialisationTolerancesMaking goodThe Clerk of Works in future development

Assistants under training by Clerks of WorksTraining by experience-Clerks of Works-in course of dutyStudy by Clerks of Works-for personalqual i f icat ionsCourses for Clerks of Works arranged bythe departmentInitial issues of technical informationto Clerks of WorksPermanent issue Set of British Standardsfor Clerks of WorksPermanent issue Set of Codes of Practicefor Clerk of WorksPeriodical InformationStudents and Trainee AttachmentsSuitable jobs for Students or traineesPlanning useful attachments

101101102102102103103104104105105106106106

111111111112112

113

113

113

114

114

115

116116116117117

119119119119120

120

121121121

xii

10 Electrical and Heating Inspectors 12111 Factory Inspector 12112 Officers of the Parks Department 122

25 Clerks of Works 1

Conditions of Service 2and General 3Administration 4

56789

1011121314151617181 92 02 12 22 32 42 52 62 72 82 93 03 1323 3

34

3 53 63 7

Hours of WorkOvert imeOvertime ClaimsAttendance recordsTemporary absence sheetsTravel Expenses-Home to SiteIncremental ScalesEstablished PositionsSuperannuationPlace of employmentTra in ingCar AllowancesLeaveLeave on building operatives’ holidaysAdditional leave for long serviceSpecial leaveApplication for leaveTermination of engagementIl lnessAccidentsSick PayAssessment BoardsLoss of Council money or propertyPersonal propertyChange of addressCorrespondencePostageVisitors to the WorksPhotographsTrade union visitorsEnquiries for HousingVisits from the PressExamination of materials in preparationoff siteRules for visits by Clerks of Works towo rkshopsI s s u e sUse of official positionG i f t s

123123123124124124124124125125125125125125125126126126126126126127127128128128128128128128129129

129

129129130130

xiii

1 Generally

2 Definition of duties

1 Duties and Responsibilitiesof a Clerk of Works

The architect-in-charge of the works is the group leader,who is charged with the whole responsibility for bringingthe project to a satisfactory conclusion.The group leader while retaining full responsibility for allaspects will usually delegate the individual job to aJob Architect who thereupon has, normally, a delegatedresponsibility for the day to day management of the job,for the quality of the work required and produced onsite, for ensuring full compliance with all drawings,specifications and instructions, for co-ordination ofthe various elements of site supervision, and for settingthe standards and quality of work required.The resident Clerk of Works on site acts in direct assistanceto the architect in these tasks and has responsibility to theArchitect for all matters related to that site.While the Clerk of Works does not carry a legal responsibilityunder the contract, the responsibility being to the architect,s/he does occupy a position of considerable trust, and by thevery fact of engagement by the Department in the capacity ofClerk of Works, has an over-riding obligation to carry outthose duties (on which outline guidance is given in thismanual) in an efficient and dependable manner with thegreatest of integrity throughout.Very briefly the Clerk of Works’ function is:1 To inspect in detail2 To report concisely3 To interpret clearly4 To record completely

and by this means to carry out that part in the JobArchitect/Clerk of Works team which has such an allimportant role in site supervision.

For many years in the department, the Clerk of Workshas been defined as:

‘the representative of the Architect on site for theday-to-day detailed inspection of works in progress, toensure that such works are executed in completeaccordance with the contract documents and with theinstructions issued from time to time by the architect-in-charge. The Clerk of Works is to see that the specifiedstandard of workmanship IS maintained; that the materialsused are of the specified quality; that constructionthroughout is sound; that the progress of the work accordswith contract requirements, and that all essential factsrelating to the work and the various stages of progress areproperly recorded '.

In 1963, there having been previously no specificreference in the conditions of contract to the Clerk of

1

Works, a new edition of the RIBA Conditions ofContract was published, and adopted by the Council.Under Clause 10, agreed by the Joint Contracts Tribunalon which the Council was represented, the Clerk ofW orks was defined as :

‘acting solely as an Inspector on behalf of the Employerunder the direction of the Architect. . . ’

3 Effect of Clause 10 This provided in effect that a Clerk of Works cannot issueinstructions; directions via the Clerk of Works become validas instructed only if confirmed by the Architect within twoworking days.This did not define the term Inspector but of course the Clerkof Works remained in the position as before of being verymuch a key person in the contract, and the Clerk of Works’basic duties vis-a-vis the Architect as before. It did howeverinterpose some not inconsiderable practical administrativedifficulties in the confirmation of every Clerk of Works SiteInstruction by the Architect within two working days of itsissue.It is extremely convenient in practice, and normallyexpeditious, that instructions should be issued, by agree-ment between the architect-in-charge and the Clerk ofWorks, to the Contractor via the Clerk of Works SiteInstruction form.

4 Definition of Clerk of To make this practicable, in fact to avoid the procedureWorks duties in issue of becoming completely unworkable, each Clerk of Works, atinstructions new briefing, should ask the architect-in-charge to define to

the Contractor at the preliminary briefing meeting the dutiesof the Clerk of Works, and have the Contractor’s agreementthereto.

5 Contractor’s attitudes Where the Contractor is one of some renown withmanagement staff fully experienced in local authoritywork any adjustment is automatically made by theContractor’s organisation to obtain the necessaryelasticity so that the contract can run smoothly.In three or four cases, however, mainly small or mediumcontractors operating with an uninformed contractsmanager, and an agent inexperienced in local governmentwork, where the Contractor’s organisation try to workpointedly to the letter of the contract (Clause 10).considerable administrative, and often technical,difficulties and frustrations have occurred with the wholecontract proceeding haltingly, and most uncomfortably,for all concerned.In the few cases such as this, where agreement on a smoothprocedure IS difficult to obtain, there will, of course, be noalternative but for the architect-in-charge to lay on a special

2

drill with the Clerk of Works and the Contractor’sconfirmation within the two working day period.

staff for

6 Specific limitations to A Clerk of Works should NOTClerk of Works duties 1 Give any direction whatever involving financial effect

without prior specific instruction from the architect-in-charge.

2 Make any alteration to any basic detail of the contractparticulars without prior approval of the architect-in-charge.

3 Approve the Contractor carrying out any remedialmeasures that may involve any workmanship techniquesnot approved beforehand.

7 Varieties of duties of A Clerk of Works may be called upon to carry out a variety ofa Clerk of Works duties, working, for example,

1 On contracts for new works of various sorts, controlledby an architectural section of the department; and thisis the normal practice.

2 With an architect in private practice on new workscontracts.

3 On Modernisation and Conversion work, Rehabilitationor Improvements and Maintenance.

4 On a ’Package Deal’ where the Architect, Consultantsand Control Staff are employed by the Contractor.

5 On temporary attachment to specialised groups in thedepartment, at County Hall; this may, for example, includespecialist piling work; assistance with training courses;work on Ground Condition reports, and on foundationrecords, in Sites Manager’s Section, Technical PolicyDivision.

It is essential that the Clerk of Works is at all times sure ofpersonal position and authority, especially on ’PackageDeals‘, and before taking over control of such a contract s/heshould discuss the position fully, with the Site Manager in thecase of the Housing Branch. In the case of otherDepartments the Clerk of Works should discuss the positionwith the appropriate Senior Officer.

8 Knowledge of contract To be efficient the Clerk of Works must have a completelydocuments detailed knowledge of the contract requirements. For this

purpose, at an early stage, s/he must be thoroughly familiarwith:1 The drawings—in full detail, and by which s/he must be

able to check work.

3

2 The Specification—which may be a separate documentfor the older, or extension, contracts, or, in the caseof the RIBA Local Authority Conditions of Contractnow used in modified form by the Council will beincorporated in the Contract Bills as work sectionpreambles.

3 Nominated Sub-contractors Specifications—with therelevant drawings. These should make clear thespecified requirements upon which the nominatedsub-contractor has been accepted.

4 The Bills of Quantities or, in the case of the newform of Contract, Contract Bills—a general under-standing and a working knowledge of these Bills isessential.

5 The Conditions of Contract—and in particular theclauses in these Conditions relating to the Clerk ofWorks, and the issue of Site Instructions.

6 Work by other departments; for example ParksDepartment.

7 Work by other authorities: for example, Gas Board,Electricity Board, Local Borough GPO.

9 Building Regulationsand Acts

The Building Regulations 1976, which came intooperation from 31 January 1977, apply generallythroughout England and Wales, with the exception ofthe Inner London Boroughs where the London BuildingActs and Constructional By-laws continue to prevail.A Clerk of Works of the Greater London Council should befamiliar with Building Regulations 1976, and with the LondonBuilding Acts and Constructional By-laws and the provisionsin these Regulations and Acts which may apply to thecontracts under supervision.

10 Co-operativewith Agent

relations While any departure from good practice or disregard ofinstructions must be handled speedily and firmly, andwhile the Site Agent (or General Foreman) must alwaysbe kept very much aware of the standard of qualitythe Clerk of Works requires, and intends to have, theestablishment of good co-operative relations betweenClerk of Works and Site Agent is an important factor inthe successful execution of the contract.It is expected that Clerks of Works, who necessarily must bepeople of judgment, should normally have little difficulty inestablishing the appropriate co-operative relationshipsrequired between the Clerk of Works and the contractor’sstaff.

11 Anticipation During the course of the work the Clerk of Works shouldlearn to sense probable sources of difficulty, and, inassociation with the Site Agent prevent such difficultyarising or overcome it as quickly as possible. Such

4

foresight springs, in the main, from experience and froma full and detailed knowledge of the contract documents.Where instruction from the architect-in-charge would benecessary or a drawing is required, this is a matter whereintelligent anticipation by the Clerk of Works is of greatimportance, and appropriate notification to the architect-in-charge would be invaluable.

12 Interpretation The Clerk of Works must be able to interpret to theContractor’s staff, all phases of the work, all detailsfrom drawings, all specification clauses and all architect’sor consultant’s instructions of any kind.

13 Inspect ion One of the most important points is for the Clerk of Works, byconstant inspection, and quiet vigilance, to discover badworkmanship at its inception, before it gets established; s/hewill in fact often be ahead of the agent in this, and while theClerk of Works should avoid doing the agent’s and generalforeman’s job for them, it is always a good tactical position tobe in.The Clerk of Works must inspect in detail, and check measureas necessary, every part of the work, and usually, as eachday’s work is carried out. It is strongly emphasised that theduty is not done, if the Clerk of Works stands by and allowsthe Contractor to proceed to the completion of a faulty pieceof work, before condemning and having the work takendown. Where, as occasionally may happen, the contractor,woodenly it may seem, but often just trying it on to see howfar it is possible to go, proceeds with faulty work regardlessof warnings this should be the subject of immediate writtenrecord, and report to the architect-in-charge.

1 4 Reporting In the matter of report, as a routine, the Clerk of Worksis to report back each week to the architect-in-charge,and verbally at all times that may be necessary andappropriate.

1 5 Recording and theJob Diary

The Job Diary is an important document for recordingthe day-to-day happenings on the job. Particularly oflate years building contractors are using extensivedocumentation to support claims, some of which may beon flimsy ground or exaggerated, and it is essentialthat the Clerk of Works should keep quite a detaileddiary.

1 6 Diary items AmongstDiary are

the items which should be noted in the Job

1 Instructions:Any directions issued to contractorVerbal instructions or information given to Clerk

of Works by architect

5

2

3

4

5

6

7

8

9

10

Verbal Instructions or information given by DistrictSurveyor or Structural EngineerDecisions taken with officers of other departments.Dayworks:Reasons for taking items as dayworksWeather:Low temperaturesHigh windsRain or snowTests:Records of tests madeWorkmanship:Any mention of bad workmanship to the contractor or toany staff.Delays:Any delays that are evident, and the reasons for them,in any specific operation, or between operations.Drawings:Any drawing, or information, that is needed or thathas been requested.Concreting:Concrete pouring, and striking of important items offormwork, if not charted on the programme.Labour:Any labour problems including overtime bans, strikes,troubles with labour-only gangs, etc.Condemned Work:Note of any condemned work, or any materialsthat have been rejected, and details of all errors, pullingdown, cutting away, rebuilding or other remedialmeasures that have had to be taken.

17 Issue of Diary

It should be routine for the Clerk of Works to write theJob Diary up as soon as possible after events, and inany case by the end of the day, so that memory is fresh.

Each Clerk of Works will be issued with a Personal Diary, sizethree days per page, for personal records and retention.In addition each contract will be issued for use as a Job Diary,a blue hard backed A.4 size lined book which is to remain onthe contract and to be treated as one of the Job documents incharge of and kept up by the Senior Clerk of Works. This isnot transferred with the Clerk of Works.If a Clerk of Works has more than one job of size there has tobe a Job Diary for each.

18 Query and Answer Book The Clerk of Works is to keep a query and answer book foreach contract.The Clerk of Works is to record and date all queries raised bythe contractor and, similarly, record and date the answersgiven by the architect, structural engineer or consultants,

6

19 Weekly report—

20 Percentage completionfigures for housing

21 Safety

etc., as the case may be.A record of any queries, raised with the architect, by the Clerkof Works should also be kept, together with dates andanswers in a similar manner.This information will assist the architect with feed-backand financial control when dealing with extensionsof time.

The Clerk of Works is to make a Weekly Report on the formprovided, to be posted so as to reach the Department notlater than noon on the Monday of each week, in respect ofthe week ending on noon on the previous Saturday. Twocopies of the report should be sent to the Department, andthe Clerk of Works should retain a further copy for reference.It is important that all sections of the Weekly Report Form becompleted by the Clerk of Works and that the percentagecompletion of the contract, as a whole, be clearly indicatedweek by week. The presence of Machine Drivers mustalways be recorded, together with the types of machine andtimes on site.

The Weekly Report form is in itself fully explanatory exceptinsomuch as an intelligent assessment of the percentage offull completion of each block, in the case of Housing, isrequired.The need for these percentage figures to have anappropriate accuracy is that when progress on site isbeing monitored by the officers of the Sites ManagersGroup at County Hall ‘equivalents’ in partially completedbuildings are counted in as well as completed buildingsin assessment of the overall progress of the contract.Therefore some accuracy in assessment of the percentageof full completion of each housing block is necessary.

It is the responsibility of the main contractor to ensurecompliance with the requirements of the Health and Safety atWork Act, and the Factories Act as set out in the ConstructionRegulations. Should the Clerk of Works consider this is notthe case, particularly in regard to access to various parts ofthe building, the Clerk of Works should report to theDepartment by telephone and make a note in the Site diary.The contractor is required by the contract to provide safetyhelmets for the use of the Clerk of Works and CouncilOfficers visiting the site. It is recommended that suchprotective clothing should be worn at all times when carryingout inspections on the site.

22 Labour disputes Immediately the Clerk of Works is aware of a labour disputeon or affecting the site, of whatsoever degree, official orunofficial, the following action is required:1 Inform the architect-in-charge by telephone

7

2 Inform the Sites Manager by telephone3 Confirm by short written report to the architect-in-charge

the same evening, with a copy to the Sites Manager4 Note the circumstances in the diary and in Weekly Report.The Building & Civil Engineering Industries have theirown working rule agreements which provides conciliationmachinery for dealing with disputes. The decision toimplement it is left to the two parties in the dispute.The Clerk of Works is not to be involved in any way, either bycomment, advice or any other action, in any labour dispute,negotiation, or discussion between a contractor and thelabour force. The Clerk of Works must be strictly andimpartially aloof from these proceedings, confining attentionto reporting as instructed.

8

2 Commencement of a Contract

1 Briefing meetings Before each contract is commenced a detailed briefingmeeting is held in County Hall at which the contractormeets the architect-in-charge and attendant officers.The contract is discussed, and contract documents anddrawings are handed to the contractor.Before the briefing meeting the Clerk of Works should obtaina small-scale layout of the site, and should visit the site, so asto be familiar with the site location, configuration, boundaries,spoil clearance position, adjoining owners, etc. The Clerk ofWorks will then attend the briefing meeting, upon notificationby the Sites Manager and will normally be issued withcontract documents, including drawings, at that time.

2 Handing-over of site Normally arrangements will be made for the Clerk of Worksto be present at the handing-over of the site to the contractor,who should commence the Site Diary and register ofdrawings from that day. The Clerk of Works will receive acopy of the Order to Commence and should make note of thecontract times allowed for the various portions of the work.

3 Siting of offices The Clerk of Works is to see that the contractor obtains theapproval of the architect-in-charge to the siting of temporaryoffices and stores: and it will be normal for this to be settledat the meeting for the handing over of the site. The Clerk ofWorks’ office should be sited in a suitably strategic positionso that the main part of the work is in view. The size of theoffice and the equipment to be provided are specified and theClerk of Works should see that they are in accordance withthe specification. The Clerk of Works should obtain theagreement of the Sites Manager to the siting, size, andequipment of the Clerk of Works’ personal office, and theconference room.

4 Telephone Unless otherwise particularly specified a separate telephoneline is required for the Clerk of Works and is required right tothe end of the contract, and early action should be taken tosee that the contractor makes application to British Telecomfor the telephone line as early in the contract as possible. Assoon as the telephone is installed the Clerk of Works shouldinform the Department. The Council checks and pays thecharges made for calls from the Clerk of Works’ telephone.

6 Datum points for The Clerk of Works is to see that the correct Benchsetting out and levelling Marks, referred to in the specification, are known to the

contractor, and that the contractor is perfectly clear as tothe building line, setting out points, and site boundaries.

9

6 Trees

7 Contractor’s nameboards

The Clerk of Works is to ensure that the terms of thespecification with regard to retention and protection oftrees on site are followed, and should make earlyarrangements under instruction from the architect-in-charge that the trees for retention are clearly marked.

If the contractor, as is usual, wishes to erect a main boardgiving a name and address and possibly those of thesub-contractors, the positron of the board is to be approvedby the architect-in-charge, and the board is to be headed‘GREATER LONDON COUNCIL CONTRACT’ in an approvedstyle of lettering. The Clerk of Works should note that noother advertisements nor any individual sub-contractors’boards are to be permitted on the site. The contractor maywish to erect further boards giving the contractor’s name andaddress. This may be done provided they are headed‘GREATER LONDON COUNCIL CONTRACT’. For the ILEA allboards are to be headed ‘INNER LONDON EDUCATIONAUTHORITY’.

8 Council notice boards Under instruction from the architect-in-charge the Clerk ofWorks is to make early arrangements for the erection of theGreater London Council notice board giving the title of theestate and the number of dwellings, and showing the Councilcrest. Notice boards are detailed on Departmental StandardDrawings.

9 Bulk supplies

10 Existing services

11 Levels over site

The Clerk of Works is to see that at the commencement ofthe contract the contractor has all the necessary requisitionforms for bulk supply articles, that they are fully understoodand that the completed forms are sent in at an early date inaccordance with the instructions given in the specification.Copies of these requisitions should be retained by the Clerkof Works.

The Clerk of Works is to be immediately conversant bymeans of the contract drawings and documents, and, ifnecessary, through contact with the Local Authority, of thepositions of all existing services, water, gas, electricity, andsewage, on or under the site, noting particularly thoseservices in the area of the excavation. The Clerk of Worksshould then see that the contractor deals with these servicesin the manner specified, instruction being sought asnecessary from the architect-in-charge.

It will be necessary for the Clerk of Works, at thecommencement of the contract, to recheck and recordthe site levels in the form of a level grid. Instructionsfor this are given under ‘SITE LEVELS ANDBOUNDARIES’.

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12 Pavements At the commencement of a contract the Clerk of Worksis to make a check of pavements immediately adjoiningthe site with the contractor and agree with a represent-ative of the Local Authority concerned the existing stateof damage to paving slabs. This will obviate anymisunderstanding that might occur at the end of thecontract as to the responsibility for breakages.

3 Site Levels and Boundaries

1 Surface levels of site

2 Fly tipping

It is essential that before any surface excavation or anyother reduction or making up of levels is carried out onthe site an accurate level grid of the site is recorded.It is sometimes the case that because parts of the sitewere covered with buildings demolished only at a verylate stage, a sufficiently comprehensive series of levelscould not be obtained prior to the commencement of thebuilding contract.For this reason amongst others, it is necessary that acheck level grid of the site be carried out immediatelyfollowing the issue of the Order to Commence.This will usually be mentioned to both the contractorand the Clerk of Works at the briefing meeting, and thecontractor will be asked to carry out the work under thesupervision and check of the Clerk of Works. The Clerkof Works. however, may well have to take the initiativeto ensure that the work is carried out, and at an earlydate.

It is sometimes found that unauthorised fly-tipping hasoccurred on a site. It is usual for arrangements to bemade with the Valuer, to remove the fly-tipped materialas a first operation, under separate accounting arrange-ments, and the Clerk of Works should make an accuratecount of the amount removed. Thereafter the site gridshould represent the site configuration without the fly-tipped material.If vehicles are discovered fly-tipping on a Greater LondonCouncil site no attempt should be made by the Clerkof Works actively to interfere. If the site has not yetbeen handed over to the contractor, however, the Clerkof Works should report the circumstances of the fly-tipping to the architect-in-charge who will transmitthat information to the Valuer.If the contractor has possession of the site the matter will bethe contractor’s responsibility.

3 Agreement and The levels, as they are taken, should be agreed between therecording of surface Clerk of Works and the Site Agent or the representative of thelevels contractor, and they should be recorded on a plan of the site.

The level record plan should be signed by the Clerk of Worksand the Site Agent. Four prints at least should be taken, twocopies are to be forwarded to the architect-in-charge for therecord, one copy retained by the Clerk of Works and one copyhanded to the contractor’s Site Agent for retention.The Clerk of Works should see that no reduction or otheralteration of levels takes place until the architect-in-chargehas seen the check levels and has issued instructions thatsuch work may proceed. If during the taking of the checklevels significant differences from the expected levels are

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apparent then the architect-in-charge should be informedimmediately so that amongst other considerationsarrangements may be made for the Valuer to be called in tosee the differences that have been noted.

4 Level book The Clerk of Works’ level book must be properly writtenup in accordance with the levelling method adopted andmust show the readings from which the levels werecalculated.

5 Datum for levels

6 Adjoining property

Levels are in every case to be relatedspecified in the contract documents.

to the datum level

It is a Clerk of Works responsibility that during construc-tion the department are good neighbours as far asadjoining owners are concerned.Arrangements (including fencing arrangements) whichhave been agreed with adjoining owners, and which arespecified in contract documents, must not be variedin any particular without referring such proposedvariation to the architect-in-charge for instructions.This is to ensure that no legal contractual arrangementsmade by the Council with parties having interests inadjoining properties are upset or prejudiced by actionof the contractor or his representatives.Directly it becomes known that a contractor contemplatesany variation from the instructions issued upon such matters,the Clerk of Works is immediately to enter a protest andreport the circumstances forthwith to the architect-in-charge.

7 Damage to property In the event of any damage to property the Clerk of Works isto make immediate report to the architect-in-charge wheninstructions as to whether certified statements andwitnesses’ names will be required. The Clerk of Worksshould also make note of the incident in the Site diary.

8 Adjoining contracts Clerks of Works are to ensure that contractors do notencroach upon areas allocated to other contractors, eitherin the execution of work, or in the storage of materials.

9 Completed services Prior to the practical completion of the contract for eachportion of the work the Clerk of Works is to have marked on aplan the details of the drainage, gas, water, telephone andelectricity services as executed. The Clerk of Works is toforward the marked up plan to the architect-in-charge at thecompletion of the work. These details will normally have beennoted on the working drawings by the Clerk of Works whenthe services were being put in.

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10 Site boundaries

11

12

Street lighting

Temporary fencingowned by the Council

Before the contractor proceeds with work on partywalls or fences the Clerk of Works should inform thearchitect-in-charge that such work is due to becommenced.It will normally be necessary for the boundaries ofsites with adjacent properties to be specifically definedand set out by the Council’s surveyors, and this will bearranged by the architect-in-charge.

In cases where lamp standards for electrical street lightingare installed by sub-contract to the main contract, it will bethe duty of the Clerk of Works to check the setting out of thestandards; and for this work the exact positions of the LEBbranch lighting cables across roads and pavements must beknown and recorded.Where the roads have been constructed under separatecontract the Clerk of Works must obtain, from the HousingEngineer’s Division, and record on drawings, the exactposition of these cables and cable junctions.

Where a contractor puts up fencing around a site thereis usually some Council fencing to be dismantled andplaced for collection; on some occasions the Councilfencing remains to the end of the contract when thecontractor is to take it down and place it ready forcollection.In either case it is the Clerk of Works’ responsibility that nofencing belonging to the Council is lost. Clerks of Workstherefore, at the handing over of a site to the contractor, areto check the amount of Council fencing in the contract and tonote this on the Weekly Report and in the Diary. In the case ofHousing Sites, when the fencing is dismantled, the Clerk ofWorks should inform the local officer of the Director ofHousing by memorandum that the fencing is available forcollection. A note should then be made in the Weekly Reportand the Clerk of Works’ diary that this has been done.

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4 Contract Documents

1 Form of contract

2 Contract drawings

The Department uses the ’RIBA Local AuthorityConditions of Contract’ modified for use by the GreaterLondon Council and the Inner London EducationAuthority, shown therein as the case may be, as the’Employer‘. In all major jobs, the Department uses‘Contract Bills’ which include the preliminaries and are ineffect a combined specification and bill separated outinto trades.The material and workmanship clauses for each trade,printed with the bill of quantities for each trade, aretermed Work Section Preambles, or Trade Preambles.In smaller contracts a specification, also containingpreliminary clauses, is bound in one volume with theconditions of contract and there are no Bills of Quantities.Under the form of contract, the tender, the Articles ofAgreement and the Conditions of Contract areaccompanied by:

Contract DrawingsContract Bills (which include Preliminaries andmaterial and workmanship preambles for eachtrade) or specification ; and these alone are thecontract documents.

The Contract Drawings compriseSet A—drawings which accompany the tender

andSet B—drawings issued with the Order to Commence.

Included with Set B are drawings showing schedules ofwork relating to:

Sub-structure and concreteBrickwork and fixing joineryDirect Supply items and plumbingIronmongeryFinishingsPainting and DecoratingDrainagePaving and Earthworks

3 Clerk of Works Under the form of contract the Clerk of Works’ duty is toin the form of act solely as inspector on behalf of the Employer undercontract the direction of the architect.

It is important to note that the Clerk of Works may givedirections to the contractor or the ’foreman upon the works’but that these directions will have no effect

1 unless they are in regard to a matter upon which thearchitect is empowered by the Conditions to issueinstructions (see below); and

2 unless confirmed in writing by the architect within twoworking days.

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4 Matters on which the In general the architect is empowered by the Conditionsarchitect is empowered to issue instructions on the following matters:to issue instructions 1 Variations to the work, including variations to comply

with statutory obligations.2 Expenditure of provisional and p.c. sums.3 Discrepancies between the contract documents.4 Appointment of nominated sub-contractors, and

nominated suppliers.5 Postponement of any portion of the work.6 Opening up work for inspection, or testing work,

materials or goods.7 Removal of faulty work, materials or goods.8 Dismissal of any person.9 Rectification of defects.10 Action in case of war.11 Errors in setting out.12 Disposal of antiquities.

5 Confirmations withintwo working days

6 Timely supplyof information

As discussed in the section dealing with the ’Duties andresponsibilities of a Clerk of Works ‘, with regard to theconfirmation within two working days of the Clerk of Works’directions, it is considered that contractors will not in thisrespect observe the letter of the contract for the majority ofthe directions given by the Clerk of Works. Nevertheless theClerk of Works should arrange a procedure in advance withthe architect-in-charge, so that if a Site Instruction that maybe arguable is resisted by the contractor, a confirmation canbe in the contractor’s office within two working days.As indicated it may not often be necessary to use thisprocedure but when it is required it needs to be readilyavailable.

There are certain specified causes of delay anddisturbance for which an extension of time will begranted and for which a claim has to be entertained.One of these is the non-receipt by the contractor from thearchitect in due time of information in the form of necessaryinstructions, drawings, details or levels, for which thecontractor has applied at an appropriate time.It is therefore necessary that a Clerk of Works shouldendeavour to foresee, well in advance, any need forinstructions, drawings, details or levels, so that advice may begiven to the architect-in-charge accordingly.Whilst it should be noted that the contractor is specificallyrequired to apply in writing for the information required, andhas the responsibility of making this written request at a timewhich is reasonable in comparison to the contract completiondate, the architect is still responsible for supplyinginformation at the right time.The Clerk of Works therefore should on no account delay

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notification to therequired.

architect-in-charge that information will be

7

8

Extension ofcompletion

Stoppages

time

9 Nominatedsub-contractorsand suppliers

of The following are the causes of delay for which anextension of contract time is to be granted:1 Late information, in the form of necessary

instructions, drawings, details or levels.2 Delay by nominated sub-contractors or by nominated

suppliers.3 Delay by direct contractors or artists.4 Variations, discrepancies in contract documents. or

postponement of work.5 Strikes, civil troubles, fire, force majeure, or exceptionally

inclement weather.6 Opening up or testing work, materials or goods.

which are found to be satisfactory.7 Unforeseen difficulty to secure labour and materials.

It is worthy of particular note that it is the responsibilityof all Clerks of Works in the Department to record dayby day in the Weekly Report the precise number of menwho are stopped through any cause (includinginclement weather), the precise number of hours, ordays, the stoppage covers, and if it is due to inclementweather, a description with some evaluation of theweather concerned. Where tower cranes or other tailplant are on site, a note of high winds causing a stop ofcrane working should be made.

Under the contract1 The contractor may not grant an extension of time to a

nominated sub-contractor without the written consentof the architect, i.e., the architect is a party to theagreement that the extension is justified. This consentto the extension would normally only be given wherethe delay in the sub-contract was not due to thesub-contractor’s own faults.

2 An extension of time is to be granted to the maincontractor if there is delay on the part of thenominated sub-contractor, provided that the extensionis only for the period by which the main contractwas in fact delayed, and that the main contractor hadtaken all reasonable steps to reduce such delay.

3 If the nominated sub-contractor fails to complete thesub-contract works in the time specified in thesub-contract plus extensions, and the architect is of theopinion that it was reasonable to have done so, thearchitect will certify accordingly in writing. It is the Clerk ofWorks’ duty to ensure that every bit of information on theprogress of the sub-contract is ready and available to thearchitect when required.

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10 Care of drawings

11 Amendments todrawings anddocuments

12 Index to Specificationor Contract Bills

13 Return of documents

14 Completion certificates

The certification the architect has to make is quite aserious matter for the sub-contractor, as it may beused by the main contractor to obtain damages fromthe sub-contractor.

4 In the case of nominated suppliers delaying thecontract by late supply the main contractor may claiman extension of time.For these various reasons the Clerk of Works shouldpay particular attention to the deliveries, the work andthe progress of the nominated sub-contractors, andthe adequacy, the timeliness, and the quality ofnominated suppliers’ deliveries.

A proper register of drawings, with dates of receipt, is tobe compiled and kept up to date by the Clerk of Works.Drawings are to be kept in a neat orderly fashion ready ofaccess when required.

When instructions are issued by the architect-in-charge,or decisions are taken on site, amending dimensions ordetail, the drawing concerned is to be marked upimmediately in ball-point pen or crayon by the Clerk ofWorks, showing the new dimension or detail; thevarious services should be indicated by distinctive anddifferent colours; or if a variation drawing has beenissued the original drawing is to be endorsed in ball-pointpen or crayon accordingly. The Clerk of Works is to makeany necessary amendments to the Specification orContract Bills in a similar manner.

The Clerk of Works will find it most useful to add to any indexof the Specification or Contract Bills by tagging the clausesneeding special note.

The Clerk of Works is to return to the architect-in-charge onthe completion of the contract, all drawings, specification, billof quantities, copies of orders, and Site Diary. The properlymarked up copy of the contractor’s programme showing thestage by stage progress of the contract from inception tocompletion is to be sent by the Clerk of Works to the SitesManager.

The copies of official orders for the execution of worksor the supply of goods constitute, when signed andcertified by the Clerk of Works, ’Satisfactory CompletionCertificates’, and they are to be forwarded to thedepartment promptly upon satisfactory completion of thework.

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5 Progress of Works

1

2

Responsibility of Clerkof Works for progress

As in the case of all other staff connected with the contractthe Clerk of Works bears a certain element of responsibilityfor the satisfactory progress of the contract and its finalcompletion to contract time. The Clerk of Works must keep inmind the contract completion date from the beginning of thecontract; to ensure that no action, or lack of action, causesavoidable delay in the carrying out of the work, and tomaintain pressure on the contractor so that the completiondates that the contract demands, or in special cases thatDivisional policy requires, are in fact achieved.The really expert Clerk of Works can exert a mostvaluable influence on the progress of a contract andthe completion of individual blocks within the timerequired.It IS incumbent upon all Clerks of Works in all divisions whomay be in charge of contracts that:1 They are to be in possession of an approved programme of

works (with adequate space for marking up) and they are tokeep this marked with the up-to-date progress positron ofeach individual unit.

2 They are to ensure that a revised up-to-dateprogramme is provided by the contractor if theoriginal programme gets too far out of date.

3 Special measures are sometimes necessary to achieveannual programmes of completions and, inconjunction with the architect-in-charge, and theSites Manager, the Clerk of Works will be expectedto participate fully in the measures necessary toachieve these programmes.

4 At the completion of the contract and before re-posting,the Clerk of Works is to deliver the marked up copy of theprogramme (original and if necessary, revised copies) tothe Sites Manager who will discuss any particularlyoutstanding aspects of the contract’s overall progress.

Weekly report—to chart The primary purpose of the Weekly Report made by theprogress of the works Clerk of Works is to record and keep check of theand factors that affect progress of the work.that progress Two copies should be sent to the Department, and one

copy be retained by the Clerk of Works.It should be noted that the position on the progressof the work should be stated with sufficient precisionfor the officer who reads the report fully to appreciatethe situation without having to refer to previous reports.The actual progress position should be related to the currentprogramme and should be given in weeks. Trades progressshould be shown in the body of the report by tradepercentage figures for each floor of each block. The Clerk ofWorks is to indicate, in the ’Progress Report’ columns of the

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Weekly Report, the precise date of the physical start of eachindividual block, the ’physical start’ being the first concretelaid, as part of the foundations.The column ’Drawings and information required’ shouldbe completed after consultation with the contractor’sSite Agent.

3 Records of labour An accurate return is to be made of the labour employed onthe site each day, recording separately the craftspersons,labourers and apprentices. In the case of sub-contract labourthe name of the firm, and trade, should be stated. Overtimehours and the absence of a necessary Overtime Permitshould also be noted.

4 Record of stoppages It is most important that all Clerks of Works in the departmentrecord day by day in the Weekly Report the precise number ofpeople who are stopped, through any cause whatsoever(including inclement weather), the precise number of hours,or days, the stoppage covers, and if it is due to inclementweather, a description with some evaluation of the weatherconcerned.

5 Potential causes of delay General observations by the Clerk of Works, in theWeekly Report, on site progress or other relevantmatters are of considerable value in assessing theposition on the site and some general observationsshould invariably be made by the Clerk of Works. TheClerk of Works must specifically note any items that aredelaying, or in the future may delay. the execution of thework.Potential causes of delay which should be noted maybe insufficient or inadequacy of labour or plant: delays inmaterial deliveries; lack of timely information ondrawings; ineffective co-ordination of sub-contractorsand delay in a sub-contractor commencing work; or anylack on the contractor’s part in organising, or arranging aproper sequence of the work.

6 Progress charts The contractor will be required to produce within onemonth of the Order to Commence a programme ofworks which should be an effective instrument for thecontractor’s site progress control, and which should bereviewed and revised as necessary during the course ofthe work. The Clerk of Works is to use a copy of thisprogramme as a Progress Chart, and record weekly theprogress position of the works; the completely marked upprogramme should be returned to the Department at theend of the contract. The contractor’s programme ofwork should include all major finishing trades and shouldbe the basis for compiling periodical progress returns for

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7 Site meetings

8

9

Marking up progresscharts

Routine records ofprogress matters

Site Meetings. An up to date programme is of coursenecessary for this, and it follows that if a contractor’sprogramme gets seriously out of date a revisedprogramme should be requested. This matter canappropriately be brought up at a Site Meeting.

Progress is one of the primary matters for consideration atthe Site Meetings held by the architect-in-charge, and theClerk of Works is to see that the architect is fully apprised ofall items adversely affecting progress, so that these mattersmay be fully examined at the meeting.At each Site Meeting the Clerk of Works should haveready in duplicate for the architect-in-charge, astatement of the progress position on each building andthe number of weeks each building is ahead of or behindthe current programme.

The Clerk of Works is to keep the Progress Chart up to date atleast weekly, and the three line method of marking-up IS to beused.The top line should show the actual percentage of workdone, in red (compared to the contractor’s programme);the second line is the contractor’s programme for theoperation, in black; and the third line the actual timetaken, in green.The marked up Progress Chart is to be exhibited on thewall of the Clerk of Works’ office. This chart at the endof the contract is one of the documents that has to bepreserved.

With labour-only sub-contracting gangs for maintrades, the question of progressing contracts, and howthe Clerk of Works should play an active part in this,requires consideration.Firstly, as has been stated, the Clerk of Works is tocontinuously record progress, clearly, against thecontractor’s programme and progress chart and have thison exhibit in his office.Secondly, the Clerk of Works is to keep the architect-in-charge fully apprised, weekly, of any fall-off inprogress in any particular trade, and give the architect-in-charge an opinion as to the reasons for this fall-off.Thirdly, the Clerk of Works is to provide the architect-in-charge with a clear statement at each Site Meeting of theprogress position of every part of the contract, agreed inadvance with the contractor’s agent, so that the matter maybe taken up at that meeting, and the contractor will be askedto give reasons, for the record, for any delays that haveoccurred.

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10 Progress difficulties There has been deterioration of late years in the generalefficiency of the building industry, and its capacity toappropriately progress work of adequate quality.This is due largely to the serious shortages of skilledand experienced trades supervisory personnel in theindustry, and the growing dependence upon labour-onlysubcontracting gangs, paid sometimes at high rates, butoften without adequate skills, and without the necessarytrades foremen to properly supervise their work.This often involves the Clerk of Works in considerable timewastage in checking, repeatedly guiding, teaching, andalmost directly supervising trade gangs. This is not goodenough and takes up too much of the Clerk of Works’ timethat should be spent on other duties.Where there is insufficient trade supervision on any jobthe Clerk of Works should consult with the architect-in-charge and the position should be ventilated at an earlysite meeting, the contractor being strongly requested toprovide the necessary trades foremen for the propersupervision of the work.

11 Errors involvingloss of time

The Clerk of Works is to note in the Job Diary where, andwhen, work has had to be pulled down, cut away, rebuilt, orreplaced, involving loss of time, the amount of time lost, anda note as to how the sequence of the later work wasaffected.

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6 Instructions to Contractors

1 Additional works No orders whatever, either written or verbal, may begiven by the Clerk of Works involving work or costadditional to that provided in the contract, without priorinstruction from the architect-in-charge. Should thenecessity for additional work arise, the question is to bereferred immediately to the architect-in-charge and noadditional work is to be put in hand until the officialinstruction is given.

2 Site instructions by Should it become essential in exceptional circumstancesClerk of Works for the Clerk of Works to give immediate written site

instructions, permission is to be obtained from thearchitect-in-charge, by telephone if necessary.1 To ensure that the instructions which may have to be

given to contractors are issued in a standard form,and that copies are appropriately circulated, books ofinstruction forms in sets are provided and must be usedfor giving out all site instructions.

2 The forms will be completed and issued by Clerks ofWorks:

(a) To convey instructions to the contractor by theClerks of Works on behalf of the architect.

(b) To confirm oral instructions given by the Clerkof Works on behalf of the architect.

(c) To convey or confirm instructions given by thearchitect on the site.

Written confirmation of oral instructions must be givenon the same day.

3 The top copy of the instruction form will bedelivered by the Clerk of Works to the contractor’srepresentative on the site and the other copiesdistributed as follows:1 copy-to be retained by the Clerk of Works in thebook;2 copies-to be sent by the Clerk of Works each weekwith the Weekly Report to the architect (one of whichwould be forwarded by the architect to the PrincipalQuantity Surveyor or appointed managing quantitysurveyor).

4 It will also be necessary to issue site instructions in thematter of heating and electrical works to the contractor forthe heating and electrical sub-contractors. Theseinstructions will normally originate with the heating orelectrical inspectors. These may be given orally subject to awritten record being issued through the building contractorthe same day. Books similar to those mentioned above willbe issued to Inspectors, but an extra copy will be availablefor the sub-contractor.The Inspector will prepare the instruction and both theInspector and the Clerk of Works will sign it.

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3 Dayworks

4 Contractor’s vouchers

5 Contractor’s paysheets

5 When issuing site instructions, whether they willinvolve a formal variation order or not, considerationmust be given to any possible effect on other trades.Thus, the Clerk of Works or Inspector, must informeach other of site instructions which may affect thebuilding work or engineering services. It will help inthis if site instructions are passed quickly to thepersons concerned so that they may make a rapidassessment of the effect on their own work.

6 Instruction forms are to be numbered seriallythroughout the contract by the Clerk of Works.

When daywork has been authorised, the Clerk of Works is tocheck the work done, the material used and the labour hoursand machine hours expended. The Clerk of Works shouldsign and date each daywork sheet, endorsing it as follows:

’Subject to approval by the architect as daywork Icertify that the time and materials as stated arecorrect.’

A record must be made on the Weekly Report, and inthe Clerk of Works’ diary, of all daywork sheets signed.In the event of disagreement with the items recordedon daywork sheets, such matters should be referred toarchitect-in-charge for decision.

It is the practice of some contractors to present theirinter-office vouchers (as distinct from authorised dayworkvouchers) to a Clerk of Works for signature, notifying itemsregarded by the contractor as qualifying under the heading ofextra or additional works.These vouchers are NOT to be signed by the Clerk ofWorks. Even though these vouchers may be annotatedby the contractor as ’for record purposes only’ theyshould not be signed by the Clerk of Works.Where a contractor presses the acceptance of thesevouchers on the grounds that under the relevant clauseof the contract they form the contractor’s notification ofworks deemed additional to that shown on originalcontract documents, then the Clerk of Works shouldarrange that the vouchers are forwarded to thearchitect-in-charge who will deal with the matter.

It is also the practice of some contractors to presentcopies of their paysheets to the Clerk of Works forsignature. These paysheets give names, trades’ hoursworked, rates and total pay of the labour employed.As the Clerk of Works is not in a position to check any ofthese items no useful purpose is served by appending asignature, and these paysheets should not therefore besigned by a Clerk of Works.

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8 Instruction to correctdefective work

In the normal course of the contract there sometimes occursfaulty work which, in the view of the Clerk of Works, shouldbe pulled down or taken out. This is sometimes so obviousthat the contractor, realising the mistake as soon as attentionis drawn to it, at once prepares to remedy the fault; and insuch cases unless structural or aesthetic considerations areinvolved, a simple notification to the architect-in-charge and arecord in the Weekly Report and Diary will suffice. In all othercases however it will be necessary to issue a formal siteinstruction.Where such formal instruction is issued to the contractorto remove or remedy defective work for which thecontractor is responsible then it must be made completelyclear that it relates to defective work which is thecontractor’s responsibility.In every instance where an instruction is required thearchitect-in-charge should be informed in detail of thecircumstance; and the method of instruction, and the time ofconfirmation of the instruction, agreed with the architect.If there occurs poor work, not necessarily the subject of a’pulling down’ instruction, which the contractor obstinatelyor evasively fails to remedy (or if the contractor persistentlyfails to comply, although warned, with any of the contractparticulars), then the Clerk of Works is to advise thearchitect-in-charge of the circumstance in writing so thatappropriate action may be taken. A copy of this advice is to besent to the Sites Manager.

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7 Site Investigations

1 General In general a Site Clerk of Works is not directly involvedin site investigation, which is completed in practicallyevery case before the commencement of the contract.Clerks of Works however are sometimes seconded to theSites Managers group for specialist duties in connectionwith site investigations; and there are some occasions inthe excavation of the very mixed soils under Londonwhen some unexpected features are revealed, possiblynecessitating, often at the District Surveyor’s request, thecarrying out of plate loading tests on site.The contract drawings include trial bore layouts andstrata section sheets in the site set of drawings on allcontracts. Therefore, as a Clerk of Works may at somestage be required to participate in some phase of siteinvestigation a few general notes on the subject wouldbe appropriate.

2 First investigation of a The first examination, or reconnaissance, of a site is carriedsi te out before the site is purchased by the Council. The site is

examined for overall suitability, and as part of this areconnaissance is carried out with specific reference to thetype of subsoil, any particular foundation difficulties that maybe met, and the likely relative cost of foundation works, andof abnormals.This involves gathering information locally and from allsources; geological survey and museum; local borough;previous user; District Surveyor; building inspector; gravel pitrecords; examination of neighbouring sites and works; andwhere necessary includes shallow hand bores using aMackintosh prospecting tool.A Ground Condition report is formulated for information whenrecommendations to the Valuer are being made.

3 Soils investigation byspecialist firms

The next step after the site has been allocated, is for ascientific soils engineering investigation to be carried outunder contract by a specialist firm.In close liaison with the Structural Engineer, term contractsare operated and re-tendered at regular intervals, for the soilsinvestigation by specialist firms, covering London in fourareas.These highly specialised firms carry out trial borings,obtain samples of soils from varying appropriate depths,take necessary site tests, eg, penetrations, carry out fullanalyses and laboratory tests of the samples taken, andproduce a report with observations and recommendations

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4 Primary purpose of term The primary purpose of the term contract iscontracts 1 To assess and make recommendations for bearing

capacities;2 To assess settlements;for the information of the Structural Engineer in hisdesign of the foundations of the project.

5 Other soilsengineering problems

The specialist firms concerned are equipped to investigateand produce recommendations for the solution of manyother soils engineering problems; and recommendationsare often sought on such problems, eg, slip, clay surfacecreep, compaction of spoil, soakaway permeabilities andwater movements, on behalf of and in liaison with theStructural Engineer, or other divisions, branches ordepartments.

6 Chemical analyses

7 Co-ordination of theoryand practice

8 Spacing of trial bores

Sulphate analyses from water and soil samplescarried out under separate arrangements.

are

It can be said that with the preliminary investigations ofneighbourhood works, the scientific soil mechanicsinvestigations by specialist laboratories, and theparticipation of the Structural Engineer and the DistrictSurveyor with the information available to them, andtheir actual down to earth practical examination of theexcavations for foundations on the site, that the bestpossible co-ordination of scientific soil mechanicstheory with hard experience and the best engineeringpractice is almost certainly realised.

Spacing of 15 m. in both directions is appropriate fora building site. When it is considered that boreholeswithin metres of each other in the London area canreveal very differing conditions this coverage of230 square metres of ground by only one 150 mm.diameter borehole is seen to be by no means too much.It is a matter of some interest when considering howmuch ground we are actually sampling in proportion tothe whole site, that a 90 m. grid, sometimes used forpreliminary explorations, means only one 150 mm.diameter borehole per approximately 0.8 hectares ofground.it is also to be noted that all specialist firms, carrying outterm contracts ‘for site investigations, issue disclaimers ofresponsibility for conditions between boreholepositions‘.

9 Sub-soil soundings The use of intermediate sub-soil soundings or other typeof penetration field tests, in areas between bores,although not particularly favoured by specialist firms can

27

often reveal in a direct and relatively inexpensive mannerhazards to economic foundation construction.

10 Code of Practice The relevant Code of Practice, Site Investigation is BS 5930(1981).

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8 Foundations

1 Setting out foundations

2 Bottoms of excavations

3 Excavation beyondcontract depth

The Clerk of Works is to check in detail that thecontractor’s setting out corresponds exactly to drawings,The Clerk of Works should also see that main centrelines are beaconed in concrete, or in timber set inconcrete, clear of excavation and reasonably freefrom possibility of disturbance so that the setting outmay be rechecked at any later stage of the foundationwork.A steel tape should be used for checking dimensions.In the event of any variation of setting out becomingnecessary, instructions must be obtained from thearchitect-in-charge, and the variation recorded in redink on the setting out plan.

The bottom of every excavation for foundations willnormally be inspected and passed by the architect-in-charge, the structural engineer, and the District Surveyoror Local Authority’s representative before any concreteis placed. The passing of foundations does not devolveupon the Clerk of Works.When depths have been reached at which inspection isdesirable, and the excavated widths and lines havebeen checked, the Clerk of Works is to inform thearchitect-in-charge who will arrange for the necessaryinspection.The Clerk of Works is to take and record the levels ofthe approved bottoms before concrete is placed. Whenfoundations bottoms are approved concreting shouldtake place without delay.

It is essential that the architect-in-charge gives priorapproval to any work which may involve the Councilin cost additional to the contract amount In particularis this so with foundations, and the Clerk of Worksmust therefore obtain prior approval from the architect-in-charge before permitting the contractor to excavatebelow the contract depth. While in most cases therequest for approval will be formality only, this formalprocedure is to be followed through in every case ofexcavation beyond contract depth.For these reasons the Clerk of Works is to:

1 Be aware of the contract depth of all foundations.2 As excavation proceeds check whether it is possible

to obtain a satisfactory foundation at depths shallowerthan contract depth, and if so, inform the architect-in-charge and request Structural Engineer’s inspectionat that depth.

3 Stop excavation within a few inches of contract depthfor Structural Engineer’s examination and instruction.

29

4 Report in every case, for confirmatory approvalbefore work proceeds, to architect-in-charge,whenever instruction is issued by Senior StructuralEngineer or District Surveyor to go deeper thancontract depth, or to widen or otherwise increase afoundation.

If a Clerk of Works has any difficulty in implementingthis instruction with a contractor the Sites Manager isto be informed.

4 Visits of Structural Whenever a visiting Structural Engineer has occasion toEngineers to Sites instruct any modification or variation of any sort on site, the

Clerk of Works wiII report the instruction (immediately andbefore any work proceeds in the special case of foundations)to the architect-in-charge and send a copy to the architect bypost the same day.

5 Concreting foundations The Clerk of Works is to ensure, before concrete is placed,that the foundation bottoms are clean and trimmed and thatthe materials, the mix, the water content and the methods ofmixing, transporting and placing the concrete are completelyadequate and fully in conformity with the specification.When concreting of foundations is in progress the Clerk ofWorks is to give continuous supervision and on no account ISto leave the works except by specific prior permission of thearchitect-in-charge and except also when the necessary reliefClerk of Works has taken over. On completion of a foundationthe Clerk of Works is to check and record the finishedconcrete levels before brickwork is commenced and is tonote the check in the Weekly Report and in the diary.

6 Records of foundations The Clerk of Works is to make precise day to daydetailed records of foundation work as the work proceeds.Immediately upon completion of the foundations of anyone block, or other structure, the Clerk of Works is toprepare a tracing on cloth or paper, in black Indian ink,giving complete details in plan form of the foundationwork to that building. The drawing is to include:1 Contract title, block identification and all necessary

overall dimensions.2 The datum level and GF finished level.3 The depths of all trenches, with all changes of level

and all relative ground levels.4 The width of all trenches, with lengths and widths

of breaks.5 The dimensions of piers.6 The top levels of concrete in the foundations.7 The date the various sections of concrete were

poured.

30

8 The mixes of concrete used and the use of anyspecial cement.

9 Space for signature by contractor’s agent, Clerk ofWorks and architect-in-charge,

The drawings are to be agreed with the contractoras being a true record of the work and are to be signedby the Contractor’s Site Agent, by the Clerk of Worksand by the architect-in-charge. Dyeline prints are thento be taken and distributed as follows :-

1 copy - Contractor1 copy - Council QS1 copy - SE (or Consultant)1 copy - Clerk of Works1 copy - Sites ManagerOriginal - Section Architect

In the Housing Branch, the ordering of dyeline printsmay be arranged via the Sites Manager’s office. Inaddition to the foundation record drawings, Clerks ofWorks, of all divisions, are asked to forward to theSites Manager a summary of foundation details, blockby block, for all structures on their contract. These arefor record in connection with site investigations andGround Condition reports. The details should be filledin on a form H.O. 251 obtainable from the Sites Manager’soffice and of which a copy is shown, attached in thisSection.

7 Physical start to The Clerk of Works is to indicate, in the ’Progress Report’individual blocks columns of the Weekly Report, the precise date of the

physical start of each individual block, the ’physical start ’being the first concrete laid, as part of the foundations.

8 Records of obstructions Where there are obstructions in excavation such asold concrete work, old brickwork or old servicessufficiently massive and durable to impede appreciablythe operation by the excavation method that is beingadopted, then a record of obstructions preciselydimensioned and detailed is to be prepared by the Clerkof Works, similar to but separate from the record offoundations.

9 Piled foundations In the case of piled foundations the Clerk of Works is tokeep a record of the progress of the piling on a copy ofthe pile layout plan. This plan should be kept up to datedaily, showing the piles driven each day, the dates ofdriving, the set obtained and the results of tests made, ifany. In addition the Clerk of Works is to complete aDaily Pile Driving Record, on a pro forma supplied by theDepartment, in triplicate. One copy is to be retained on

31

site and two copies forwardedwith the Weekly Report.

to the architect-in-charge

10 Water in excavatedfoundations

11 Extent of excavations

12 Safety in excavations

13 Objects of antiquity

Where running water or a ’spring’ is encountered infoundations the Clerk of Works is to inform the architect-in-charge so that instructions may be issued for dealingwith the matter adequately. Where continuous pumping isfound to be necessary and there is a possible danger ofdrawing water from near foundations the Clerk of Worksis immediately to inform the architect-in-charge who willissue instructions.

The Clerk of Works is to ensure that excavation for afoundation does not in any way endanger adjacentfoundations or piling, by being excessively sloped back,improperly strutted or extended to an undue distanceoutside its own boundaries. In bad ground there is oftenthe possibility of this occurring.If in the Clerk of Works’ opinion there is any likelihood ofadjacent foundations being at all affected, then the Clerkof Works should halt the work of excavation and seekinstructions immediately from the architect-in-charge.

It is a requirement of the Council’s specification that thecontractor maintain excavations in a safe and satisfactorymanner. If at any time, in the opinion of the Clerk of Works,excavations are not being maintained in such manner, e.g.,excavation to depth in loose ground without essentialtimbering, then the Clerk of Works is to draw the contractor’sattention to the matter and make a note in the diary that thishas been done. If the contractor does not remedy the matterthen the Clerk of Works is to report accordingly to thearchitect-in-charge.

The Clerk of Works is to obtain from the Department aprinted ’Reward’ notice dealing with objects ofantiquity found on the site and to arrange for the displayof such notice in a prominent position during the periodsof excavation. The Clerk of Works is to collect anyobjects of antiquity which may be found during theexcavations and deliver them to the architect-in-charge.When such articles are located in excavations and are noteasily movable, work on the spot and in the immediatevicinity is to be suspended and the architect-in-chargenotified by telephone immediately, who will arrange forwork to be renewed under special supervision.Immediately upon making a ‘find’ the Clerk of Works should,unless absolutely certain that it is of no interest, notify theJob Architect and Historic Buildings Division (Tel.01-633-5871). Historic Buildings Division will arrange an earlyvisit to the site or failing this give instructions as far as

32

possible over the telephone. If an isolated object is brought tothe Clerk of Works an attempt should be made to ascertain(and state in a report for HB Division) the depth and type ofsoil in which the buried object was found, with a sketch of thelocation in relation to the rest of the site. If the find or part of itis still undisturbed the Clerk of Works should immediatelyconsult the Historic Buildings Division and isolate the relevantpart of the site until the Historic Buildings Division inspection(which will be immediate) has been made. Any decision toisolate a part of a site which might lead to a claim by thecontractor for delay, shall be the subject of an immediatereport by Historic Buildings Division (in conjunction with thedivision concerned) to the Executive Committee and thePlanning Committee.Historic Buildings Division will take into careany isolated find. They will arrange, as a matter ofimmediate urgency for the inspection of finds wherework on the site has been affected and will makerecommendations to the executive division on any specialarrangements which may be necessary for theuncovering or preservation of antiquities. If specialistsupervision of such work is desirable the arrangementswill be made by the executive division concerned on theadvice of the Historic Buildings Division.

14 Cultivation of areas to be Clerks of Works are to ensure that areas that are to beplanted or grassed soiled, planted or grassed are properly cleared of debris

and obstructions to the depths and in the manner laiddown in the Specification; and Clerks of Works are topersonally check that this work has been efficientlycarried out.

15 Informat ion The following are useful sources of information onfoundations :1 Foundations and substructures. Code of Practice CP 101 :

1972 : not more than four storeys.2 Foundations. Civil Engineering Code of Practice CP 2004 :

1972.3 Soils and Foundations, BRS Digests Nos. 63, 64 (revised

1972) and 67 (revised 1980).

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GREATER LONDON COUNCIL

DEPARTMENT OF ARCHITECTURE AND CIVIC DESIGN

RECORDS OF GROUND CONDITIONS IN GREATER LONDONRef. AR/TC/SW

Division

Architect

Structural Eng.

Clerk of Works

Date

Site Location

Contractor

SUMMARY OF FOUNDATION DETAILS (AS EXECUTED)

BlkNoand

Type

No ofStoreys

TYPE OF FOUNDATION(Inc. Width of Trenchesand Depth of Concrete.)

Depth of Digor Length of

P i l e sMin. Max.

Remarks-(e.g. Water trouble, strata penetrated, obstructions encountered).

Type of SubSoil on

which FoundationRests

3 4

9 Drainage

1 Checking levels andlocations of existingsewers

Where the proposed drains and sewers are to connect to anexisting soil and/or surface water sewer the Clerk of Works isto check the location of these sewerss against the drawingsand is to check the levels of the existing sewers against theBenchmarks referred to in the specification. The Clerk ofWorks must also contact the Engineer of the Local Authorityin whom the sewers are vested so that L.A. staff maypositively identify the sewers to which connection is to bemade. All these checks are to be made before work on theproposed sewers and drains is started and the Clerk of Worksis to inform the architect-in-charge immediately of anydiscrepancies.

2 Setting out

3 Excavations

The Clerk of Works is to check the setting out of manhole andinspection chamber positions and the location of drainageruns before excavation is commenced. In particular s/he is tocheck that the distances between manholes and chamberscorrespond to those shown on the drawings. Anydiscrepancy in these distances must be reported to thearchitect-in-charge as differences in distance may requireadjustments in invert levels to maintain satisfactorygradients. The Clerk of Works is also to check and record thelevels of all pegs and site rails and the constructed levels of allmanholes and inspection chambers as the work proceeds.

The Clerk of Works is to inspect the bottoms of all drainageexcavations before any pipes, concrete or granular beds arelaid. Should it be considered that the bottom of theexcavation or any part of it is not suitable for the type ofconstruction proposed, the Clerk of Works is to inform thearchitect-in-charge and obtain approval for any work requiredadditional to the contract. Such works may include thedigging out of soft places and replacing with good material,the construction of land drains in the trench bottom to keepthe excavations clear of water and possibly a change in themethod of support proposed for the new drain or sewer. TheClerk of Works must also check and record the levels of alldrainage excavation prior to the construction of the drainageworks. The Clerk of Works is referred to Section 8’Foundations’ of this handbook where a number of relevantprovisions regarding the supervision of excavation works canbe found.

4 Support and protection The Clerk of Works is to ensure that the contractof the proposed sewers requirements regarding the support and protection of theand drains proposed sewers and drains are complied with by the

contractor and is to keep records, counter-signed andagreed by the contractor, of all concrete, granular orother materials provided by the contractor for the supportand protection of the sewers and drains.

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5 Backfilling

6 Timber left in

The Clerk of Works is to ensure that the specificationrequirements regarding backfilling are scrupulouslyobserved. In particular it is important that fillingimmediately over pipes is carefully placed and that theremainder of the filling is thoroughly consolidatedin layers and watered if necessary. Backfilling aroundmanholes, particularly when these are located in roads orpaved areas, must also be carefully compacted asdescribed above.Proper consolidation of backfill is a job that is frequentlyskimped if not properly supervised and can lead toexpensive reinstatement works at a later date.

Should it be considered that in order to preserve the stabilityof existing or proposed structures, it is desirable to leave incertain sections of excavation timbering, the Clerk of Worksshould inform the architect-in-charge and obtain thearchitect’s authorisation. A record agreed by the contractor isto be kept of the amount and location of all timber left in.

7 Testing of sewers and The Clerk of Works is referred to Section 21 ’Testing‘,drains for information regarding the testing of sewers and

drains.

8 C o n n e c t i o n sewers

to existing

9 Handing overand drains

o f sewers

Before making any connections to existing sewers theClerk of Works is to contact the Engineer of the LocalAuthority in whom the sewers are vested to ascertainwhether there are any particular requirements that mustbe observed. It may be found that the Local Authorityinsist on making the connection themselves in which casethe Clerks of Works must co-ordinate this work with thatof the contractor.

Before completion of a contract the Clerk of Works is toensure by rodding that all drains are clear and free fromobstructions and all drains are to be tested for soundnessimmediately prior to handing over. Before undertaking thiswork the Clerk of Works must contact the EnvironmentalHealth Officer of the Local Authority to obtain details of thetests required by the Local Authority and to arrange for theEnvironmental Health Officer to be present when the testsare carried out. The Clerk of Works must record in detail in theSite diary all tests of drains and should obtain a signedacceptance from the Environmental Health Officer for alllengths of drain that are accepted as satisfactory.

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1

2

3

4

Code of Practice 110

Developments

Types of Concrete

Definitions

10 Concrete and ReinforcedConcrete

By a combination of various codes, relating to concrete, into aUnified Code, a Code of Practice 110 entitled ’The StructuralUse of Concrete’ was introduced in November 1972.With the complete omission of the classical elastic theory,the theory of Limit States, which has internationalacceptance, has been developed and used in the code, withstatistical probability calculations being used for loads,strengths, and control checks.The resultant Code of Practice 110 ’The Structural Use ofConcrete’ is very much in advance of, and different from,anything of this type that has been produced before. Exceptfor general background information this need not concern theClerk of Works, but in the immediate future as therecommendations of the Code of Practice are graduallyabsorbed by the industry some alterations in specificationrequirements and in the sophistication of constructionmethods and control will undoubtedly take place.

The possible future site control developments willcertainly be of interest to the Clerk of Works, and in viewof the present developing stage of structural concretetechnique generally, it would be as well that a fewdefinitions of practical interest should be given.

1 Ordinary Structural Concrete, produced by:(i) Prescribed Mixes, or(ii) Designed Mixes, or

2 Special Structural Concrete, produced by:(i) Prescribed Mixes, or(ii) Designed Mixes.

1 Ordinary Structural Concrete:Is in general terms, any grade of concrete made fromPortland cement, natural aggregates and water.

2 Special Structural Concrete:Is in general terms, concrete made with specialcements, e.g., High Alumina, or with admixturesor special aggregates.

3 Prescribed Mixes:Are in general terms what we have hitherto callednominal mixes. These are relatively rich in cement andare used when it is considered that the additionalexpense of establishing a designed mix andstatistically controlling it by works cube tests, is notiustified.

4 Designed Mixes:Are mixes designed by the Contractor or the supplier tocomply with the strength requirements demanded by thespecification. To ensure an appropriate durability, the

37

minimum cement content and a nominal maximum size ofaggregate will be stipulated.Unless specified otherwise it will be the Contractor’sresponsibility that the workability of the concrete issuitable for the particular handling and placingconditions.The Contractor must:(a) Demonstrate that the mix design is satisfactory

by a series of trial mixes, or evidence of previoussatisfactory use.

(b) Employ a technically qualified supervisor incharge of the concrete work.

(c) Maintain a comprehensive statistical control onthe cube test results continuously during theprogress of the concrete work.

5 Demonstration that A point that the Clerk of Works should not overlook isdesigned mix achieves that whilst the designed mix is being established to suitthe appropriate surface the constructional requirements of the contract, thefinish contractor must also demonstrate that the designed mix

will satisfactorily achieve the appropriate surface finishrequired by the architect-in-charge. The Clerk of Worksshould talk this feature over with the architect-in-charge and if necessary with the structural engineer.

6 Grades of Concrete Grades of concrete are tested by 28 day strength inNewtons/mm2, and the particular grades are chosen bythe designer after consideration of the type of use,characteristic strength required and exposure conditionsand cover provided.

7 The London Building Act The London Building Act refers to nominal mixes forthe various grades of concrete (opening the way fordesigned mixes in Table 10). A required minimumcrushing strength for control purposes by means ofworks cube tests is stated in every case.

8 Departmental Preambles The Departments standard preambles also quotenominal mix figures for the various grades of concretebut includes minimum cement content safeguards.If the contractor requests the substitution of designedmixes, the Department has full alternative specificationinstructions available in the preambles to introducefully controlled designed mix techniques immediatelythese are required.

9 Proportioning Materials The Clerk of Works must note that, in whatever wayon Site concrete is specified, the actual proportioning of

materials for making concrete on site, other than liquids,must be done by weight, and by no other means, unlessspecial and particular approval is given otherwise.

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10 Frequent test cubes

1 1

12

Calcium chloride inconcrete

Change in materials

13 Competent supervisionby contractor

In the translation of volumes to weights when requiredthe Clerk of Works should consult the structuralengineer.

In designed mixes, as has been mentioned, the contractoris required to maintain continuous control by cube tests.the results of these being subject to statisticalinterpretation. The reason is, as the Clerk of Works willnote, that the contractor has almost completeresponsibility for the concrete mix, and the operationsgenerally to produce the concrete.It is therefore necessary for the site control to monitorvery carefully and continuously the strengths of theconcrete we are in fact getting from the contractor.

It is a Departmental Instruction that calcium chloridemust NOT be used as an additive, either as calciumchloride or under any proprietary name, in any insitu orprecast work containing reinforcement or embeddedmetals, where either

(i) the concrete is exposed to the weather, or(ii) the concrete is exposed to damp conditions

internally, or(iii) the concrete is steam cured, or(iv) the cement is any other than Portland Cement or

Rapid Hardening complying with BS 12, or(v) the concrete cover to any reinforcement or

embedded metal is less than 1 inch (excludingany exposed aggregate), or

(vi) the embedded metal projects from the concrete(e.g., stair case railings), or

(vii) the concrete is to be prestressed.The use of calcium chloride additive is not called for inthe Council’s contract documents and its use is strictlypermissive. Where contractors apply for permission touse calcium chloride, approval may only be given afterconsultation with the Structural Engineer.

With designed mixes, if a change is made in theor proportions, fresh trial mixes must be made.

materials

With designed mixes a contract requirement is that a namedcompetent supervisor of adequate technical qualificationmust supervise all stages in the preparation and placing of theconcrete. If the Clerk of Works considers that this work is notin fact receiving adequate supervision the Clerk of Worksshould bring this to the immediate attention of both theStructural Engineer and architect-in-charge.If due to this inadequacy the results of control test cubes aredoubtful then when the interpretation of the results of thetest cubes are made by the Structural Engineer, s/he will

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14 Ready mixed concrete-choice of depot

15 Minimum cementcontent-ready mixedconcrete

16 Careful check of readymixed concrete byClerk of Works

17 Check of delivery times-ready mixed concrete

18 Disclosure of additives

19 Mixing concrete on site

40

advise the architect-in-charge of the recommended course ofaction, both technically and for future concrete supervision.

A good deal of concrete used on sites today is deliveredto site ready mixed.Should a contractor wish to use ready mixed concrete s/hewill usually be required to make written application statingfrom which firm and depot the concrete will be supplied.The architect-in-charge will consult the Officer i/c TestingStation who will vet the supplying firm and the specific depotproposed, and advise the architect-in-charge of therecommendation.

For ready mixed concrete the minimum cement contentshould be marked on the ticket for each ready mixeddelivery.This is a most important requirement because it ispossible to produce a concrete in which the cementcontent, although sufficient to produce the requiredstrength, is insufficient to produce the requireddurability.The Clerk of Works should normally refuse to acceptdeliveries of ready mixed concrete where the cementcontent is below the amount specified, or is not markedon the ticket, and should consult the Structural Engineeron the matter.

Ready mixed concrete requires a careful check by theClerk of Works, including the regular taking of slumptests as well as the regular taking of test cubes.The concrete must comply with Clause 7 of BS 5328, but inall other respects with the Department’s requirements.

The Clerk of Works should additionally check the deliveryticket to see that the concrete is being delivered within theperiod specified in Clause 7 of BS 5328 which for a truckmixer or agitator is within two hours, or for non-agitatingdelivery equipment is within one hour of mixing.

The supplying firm must make ‘disclosure to theCouncil’ of any additives that have been incorporatedin the mix, and of the brand of cement used.

The Clerk of Works should check the weighingaccuracy of the mixing plant before concreting

2 0 Materials forconcreting on site

21 Marine aggregates

22 Gauge Boxes

23 Mixer size

24 Formwork

commences and thereafter every morning when concret-ing is in progress.A convenient way of doing this is by using bags ofcement as check weights.All mixers must be fitted with water gauges which mustbe maintained in good order. It is advisable to checkthat the water gauge is accurate by measuring thequantity of water actually entering the drum when themixer is running. This check should be made at thebeginning of the job, and occasionally thereafter, andwhenever the mixer is moved.If the aggregates are wet, an adjustment should be madeto the quantity of the mixing water.

The Clerk of Works is to ensure that the fine and coarseaggregates are satisfactory in grading, quality and cleanliness,in accordance with the specification and are stored on a cleanhard standing with the fine aggregate separated from thecoarse aggregate by a suitable partition. The Clerk of Works isalso to be satisfied that the cement is fresh, is storedsatisfactorily off the ground in a damp proof shed, and thatthe contractor uses the cement in reasonable rotation ofdeliveries.

When marine aggregates are being used in eitherready-mix or site mixed concrete, the Clerk of Worksshould make arrangements to visit the suppliers’ depotand supervise the taking of aggregate samples (bothfine and coarse) for submission to the Testing Stationat County Hall (see Section 21, item 12).The frequency of testing will be agreed between thearchitect, the officer-in-charge of the Testing Stationand the Clerk of Works prior to the commencement ofthe contract.

If. very unusually, volume batching is permitted theClerk of Works must personally check the gauge boxes,and in use make due allowance for the ’bulking’of sand, the size of gauge boxes being such that acomplete bag of cement can be used with each mixing.

The use of a mixer much bigger than necessary for themix regularly used (for example the use of a 14/10mixer for a one bag 1 :2 :4 mix) should be discouragedas far as is practical, as with this practice there is atendency for the mix to be overloaded with aggregatewhen supervision is inadequate.

The Clerk of Works must be satisfied of the adequacy of theformwork, as to line and level, tightness of joints, strength

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25 Cleaning out Formwork

26 Placing of concrete

against deflection and smoothness of surface.The Clerk of Works should check that the mould oil used isreasonable, that the Contractor does not build the formworkso that parts of it are trapped during the striking operation,that side forms of beams may be struck without disturbingbeam bottoms. On such similar matters borne of experience,the Clerk of Works could well advise the agent or shutteringforeman to mutual benefit.

Cleaning out of formwork should be done before thepositioning of formwork makes access difficult orimpossible; and a final check should be made by theClerk of Works immediately prior to concreting. If theformwork is cleaned by blowing out with compressedair, the Clerk of Works must ensure that, for examplethe floor rubbish is not blown into the boxed out columnshuttering where it can do the greatest damage. Thissort of thing is far from being unusual.

The Clerk of Works must ensure that the provisionsof the specification with regard to placing concreteare correctly observed, particularly with regard to :placing in cold weather; placing without segregation ;placing before concrete has become too stiff to beefficiently compacted ; prevention of disturbance toreinforcement during placing ; very thorough compactioneither by vibration, tamping or rodding ; prevention ofdisturbance to the concrete after placing andcompaction.A Clerk of Works will often find it necessary to consultwith the contractor as to what will constitute a day’swork, so that construction joints if found necessary,occur in the appropriate position, and the contractoris not for example caught out by darkness part wayacross a bay.

27 Construction joints There is another important aspect of construction joints,as well as determining the days output. The structuralengineer may have reservations regarding the locationof construction joints in certain vulnerable structuralpositions, while the architect-in-charge will beconcerned that joints exposed to view will not adverselyaffect the appearance of the building. It should berealised that it is virtually impossible either to form ajoint that cannot be seen or to avoid a variation in tonebetween one casting to the next.For these reasons, before any important pour ofconcrete, the Clerk of Works should check theproposed position of the construction joints with both thestructural engineer and the architect-in-charge.

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2 8 Concreting in coldweather

Unless special measures are taken no concreting shouldnormally be permitted by the Clerk of Works when theatmospheric temperature is below 3ºC, or where thetemperature of the concrete cannot be maintained at3ºC or above throughout the placing, curing andhardening periods.No frozen or frosted aggregate should be permittedto be used on any account.Where the contractor proposes to take special measureseither by the use of admixtures, special cements and/orheating of the materials, the Clerk of Works should not givepermission for these without authority but should refer to thearchitect-in-charge for instructions.For the guidance of a Clerk of Works it should be notedthat the use of admixtures alone (or special cements)is of very little practical use without special pre-heating;shielding and post-heating precautions.Concreting, especially of suspended reinforced work,will therefore not be permitted in freezing weather wherethe contractor proposes to use the admixture alone.A maximum and minimum thermometer will be supplied bythe Council for the use of the Clerk of Works, and a jacketedconcreting thermometer will be supplied by the contractor aspart of the normal concreting equipment, and may be calledfor as required. In frosty weather the Clerk of Works shouldrecord external temperature in the Site diary and in theWeekly Report.

29 Compaction of Concrete The presence of 5% voids in concrete can reduce itsstrength by 30% and very considerably reduce itsdurability. It is therefore essential for the Clerk of Worksto ensure that all concrete is thoroughly compactedunder the direct supervision of a competent member ofthe contractor’s staff.Where immersion vibrators are used they should beinserted vertically at not greater distance than about500 mm apart, and withdrawn very slowly when airbubbles no longer come to the surface.Vibrators should not be used to move concrete laterallyas this causes segregation, nor should they be broughttoo close to the formwork where sand runs may becreated.Particular attention should be given to vibration at thetop of a lift, e.g., in a column or wall.

30 Curing and protection Proper curing and protection of the concrete inaccordance with the specification is of the utmostimportance. Unless the Clerk of Works maintains a

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31 High alumina cement

firm watchfulness on this matter right from the beginningthe operatives may tend at the end of the day’s workto carry out the curing and protective measures in aperfunctory and inefficient manner.The Clerk of Works should therefore take care to see thata good routine is firmly established.Concrete that will be exposed to air (and in particularconcrete having a high class finish) must be protectedfrom damage to arrises or face and from being disfiguredby grout, or other droppings, or staining from standingscaffolding or reinforcement.

The policy of the Greater London Council on the useof high alumina cement is specified in InformationNote 13/74 dated September 1974 and is as follows :‘The use of high alumina cement for structural purposesincluding foundation work is PROHIBITED untilfurther notice unless specifically recommended by theStructural Engineering Division’.All reference to high alumina cement concrete has beendeleted from the Code of Practice CP 110 Part 1, 1972by Amendment No. 1 dated August 1974.In addition to the above, the London Building(Constructional) Amending Bylaws 1974 came intoforce on 1 July 1975. These bylaws prohibit the use ofhigh alumina cement for structural work without theprior approval of the Council.If high alumina concerte is specified care is required:

(i) No trace of other cements or limes should be lefton plant or tools used for making or handling highalumina concrete. If high alumina cement is allowedto come into contact with cement of a differenttype a ’flash set’ will take place.

(ii) All formwork should be watertight and saturatedin water when the high alumina concrete is placed.

(iii) All formwork and props must be left in positionfor a minimum period of 24 hours.In frosty weather this period must be extended bythe number of days during which the temperatureis at freezing point or below.

(iv) Lifts of concrete in mass should not exceed 300 mmand time should be allowed for the heat todissipate, the next lift not being poured for 12hours after the first.

(v) The evolution of heat from high alumina cementconcrete is considerable, particularly between6 hours and 12 hours after mixing, and to prevent’dry-out’ it is essential that the Clerk of Worksensures that the work is kept thoroughly wet, andcovers and formwork saturated for 24 hours.

44

32 Reinforcement

33 Provision for pipes

34 Striking of formwork

High alumina cement concrete should not be mixed orplaced if the temperature at the point of placing isliable to be over 27°C. It is a matter of some interestthat high alumina cement concrete, even after theinitial curing, can be seriously affected by continuousexposure to hot (over 27°C) and wet conditions. Inaddition it is thought that high alumina cement mixturescan be adversely affected by alkalis.

The Clerk of Works must see that the provisions of thespecification with regard to steel bending, fixing, and placing,are carefully and accurately, carried out. This must bechecked in considerable detail to ensure that every bar is ofcorrect size and length, is properly scaled and clean, iscorrectly bent, is in correct position laterally and vertically, hasproper cover, and is securely wired with tying wire. The Clerkof Works should make this detailed check of thereinforcement with the detail drawings out on the site ofwork, before the engineer’s or District Surveyor’s inspectionand before permission to place concrete is given. BS 4466gives guidance on bending dimensions.As the top reinforcement in a balcony is usually light, veryconsiderable care has to be taken that the contractoradequately supports the steel and does not in any waydisplace it when concreting. For this reason it is required thatthe Clerk of Works (unless specially relieved by the ResidentEngineer) personally sees the placing of every bit of concreteon all such balconies under supervision, and carefully andpersonally ascertains that the steel reinforcement is correctlyin position and remains so.At the same time as checking the reinforcement, theClerk of Works is to see that the formwork, particularlybeam and column pockets, is properly cleaned out andthat electricity and similar conduits are firmly secured intheir correct positions.

Cutting away of reinforced concrete work is not to bepermitted without the special prior consent of thearchitect-in-charge or engineer. For this reason a verycareful check must be made by the Clerk of Worksbefore the concreting operation is commenced that allplumbing, heating pipes, etc., are properly set inposition or that proper provision is made for them, inaccordance with the specification, by boxings or otherspecified method.

A Clerk of Works will often receive pressing requests from acontractor for permission to strike formwork earlier than the

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35

36

Damaged or defectivework in general

specified times, with various reasons given. On no accountwhatsoever must the Clerk of Works without authority permitthe reduction of the specified striking times, even to a verylimited extent.Only by specific and definite instructions from thearchitect-in-charge or the structural engineer may anysuch reduction be allowed, and in practice permissionfor this will rarely be given.

In the case of damaged or defective concrete, in particularwork affecting the surface finishes, the architect-in-chargewill direct as to whether the work is to be entirely renewed,or may be rectified. On specially textured surfaces where anysuch rectification work depends on the ability of amaking-good craftsperson to match the existing work, then itis necessary that the remedial work be undertakenimmediately. Excuses for postponing the remedial workshould not be accepted.If in fact the contractor does procrastinate in the remedialwork required on any concrete surface, the Clerk of Works isto report the circumstance in writing to the architect-in-charge, and to the Sites Manager, so that appropriate actioncan be taken. The circumstances should also be noted in the’General Observations’ column of the Clerk of Works’Weekly Report.This applies to surface defects of any kind, and includesbadly made construction joints.

Specified surfacefinishes

Any specification requirements relating to surface finish,must, as befits an architect’s department, be strictlyobserved.Matters relating to particular types of finish are asfollows:1 Smooth faced concrete surfaces to be painted:

The formwork should be struck as early as permitted bythe specification and at the discretion of the Clerk ofWorks. Minor defects such as small air holes may be madegood by rubbing down the whole surface with the planedend grain of a block of wood and a limited amount of water.It is preferable that no cement or sand be added during thecourse of this operation, provided that enough ’ fat ’ can beworked up from the original work. The use of a steel trowelshould be prohibited under all circumstances. Work withgreater imperfections should be brought to the attention ofthe architect-in-charge, and no remedial work should beattempted until the architect has inspected the work andagreed to the proposed remedial method.

2 Smooth-faced surfaces to be left unpainted:These should satisfy the standard for painted workdescribed above with the additional requirement that

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37 Colour

the work should as far as possible be of even colour.Since it is impossible to avoid variations in tonebetween one pour and another, individual membersshould be completed in one pour wherever possible.Any making good other than rubbing down (withoutsand and cement) will inevitably show and mar theappearance, and for that reason should seldom beundertaken, and then only after the agreement of thearchitect-in-charge.Minor defects in their original state will frequentlyprove to be less noticeable than the results ofattempts to make good.Where some making good is considered, in agreementwith the architect-in-charge, to be unavoidable,consideration should be given to the incorporation of aproportion of white cement in the repair mix to avoid thedarker tone usually associated with repair patches.Patched areas should be kept moist for several days, andthe repairs should be carried out by a skilled craftsperson.

3 Exposed Aggregate Finishes:The Clerk of Works should check that the full cover ofreinforcement is obtained, bearing in mind that in thesurface operation some small amount of material maybe removed from the concrete face.Bush hammered surfaces will usually incorporate anuntooled margin as it is not practicable to work closeto the edge of a member without damaging the arris.Tools of unequal sharpness should not be used on thesame panel.

Where it is specified, or directed, that certain parts of thework shall be executed in concrete having a uniformcolour it is important that the Clerk of Works ensuresthat all the cement supplied for that work is obtainedfrom the same source, and that the contractor hasinformed the manufacturer of the requirement foruniformity of colour.The Clerk of Works must also check that the sandsupplied for such work is of uniform colour and removeany that fails to match the approved sample.The Clerk of Works must also ensure that the water contentof each mix is constant as a small variation will lead to achange in colour and tone. It is also important that thereshould be no variations in the mix proportions particularly withregard to the ratio of cement to aggregates.

38 Vertical alignment and It is notoriously difficult without skill and care for constructionsetting out in multi- gangs to maintain strict accuracy of the vertical alignment andstorey reinforced the horizontal setting out of all the structural reinforcedconcrete work concrete multi-storey members, walls, floors, columns and

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39

beams in high rise work; but the very best of care must betaken by the Clerk of Works to see that such accuracy is infact obtained by the contractor throughout the work, andstipulated tolerances not exceeded.This must of necessity involve accuracy checkmeasurements at regular intervals; either by the Clerk ofWorks; or by a special team as part of a Quality Controlprogramme; or by the contractor carrying out specifiedaccuracy measurements under appropriately skilledengineer control, using steel tape, level, theodolite andautoplumb as required in the presence of, and recordedby, the Clerk of Works, to demonstrate that theappropriate accuracy has been obtained.This is of particular importance in the case, for example,of brickwork skin cladding the reinforced concretestructured multi-storey buildings where brickwork skinsledge on concrete nibs, and therefore the maintenanceof a strict accuracy in the basic reinforced concretestructure is absolutely essential.

Clerk of Works to seek The arrangements to be made will be laid down by theinstructions on accuracy architect-in-charge advised by the structural engineer beforemeasurements that are the contract begins; and where a Clerk of Works has a tallto be taken block contract or any contract where the accuracy check

measurements, that it is necessary to take, form a fairlyextensive programme, then the Clerk of Works should besure to take instructions in the matter, at the beginning of thecontract from the architect-in-charge.

40 Designed Mixes—FieldControl Samples andTest Cubes

For field control checks of designed mixes, apartentirely from the trial mixes originally made to determinethe design of the mixes, the following samples ofconcrete are to be taken:1 A sample of the mixes on eight separate occasions

during each of the first five days of using a particulargrade of concrete.

2 Thereafter at least one sample on each day thatparticular grade of concrete is made.

If the cement in the mix is Portland cement two cubesare to be made from each sample, one 7 day and one 28days.If the cement is High Alumina one cube is to be madefrom each sample for one day test.The Clerk of Works will note that this means 80 testcubes in the first five days for Portland Cement concretewith two cubes each day thereafter; and 40 test cubesin the first five days for High Alumina cement with onecube each day thereafter.The Clerk of Works should remember that Field Controlcube strengths are to be the subject of a continuous

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statistical checkdesigned mix.

during the whole of the work with a

41 Nominal or Prescribed For field control checks of nominal or prescribed mixesMixes—Field Control three separate samples shall be taken from placedSamples and Test Cubes material at the time of concreting.

In the case of Portland Cement each sample is toprovide one 7 day and one 28 day cube i.e., 6 cubes inall, for each concreting operation.In the case of High Alumina each sample is to provideone cube for test at the age of one day, i.e., 3 cubes inall, for each concreting operation.

42 B.S. references forsampling, slump andcubes

The Method of Making Test Cubes is fully detailed inBritish Standard 1881. Part 3. 1970.The Method of Making a Slump Test is fully detailed inBritish Standard 1881. Part 2. 1970.The Method of Sampling Fresh Concrete is fully detailedin British Standard 1881. Part 1. 1970,and all these British Standards, with others, form partof the British Standards in the permanent issue set forClerks of Works.

43 Covermeter checks Covermeter checks for steel positioning on parts such ascantilever balconies and spanning stair flights, aremandatory, the features to be checked being decided inadvance by the architect-in-charge in cooperation withthe superintendent of works, with, if necessary,structural engineer guidance. These are to be recorded.

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11 Brickwork

1 Setting out ofbrickwork

2 Datum for brickwork

The setting out of the brickwork is to be checked by theClerk of Works with relation to the established centreline of the building and the given ’building line‘. Alldimensional checks should be made with a steel tape.Regular checks should be made as the work rises. The Clerkof Works, who must be thoroughly familiar with thebrickbond specified, is to check that the setting out of the firstcourse of ’neat work’ is accurately and intelligently done sothat irregular or broken bond is avoided and the cutting ofbricks reduced to a minimum.

The Clerk of Works is to check that the bricklayers areworking from proper datum levels either pegged andprotected or incised on walls or columns.A convenient basic datum is the finished floor level(FFL) of the ground floor.The Clerk of Works should strongly encourage the use ofstorey rods which should set out storey heights in relation tosite datum level, and show heights of tops and bottoms ofopenings, course levels, and other features. The use of storeyrods is now a specified requirement and the Clerk of Works isto be thoroughly familiar with the clause concerned.

3 Damp-proof courses The Clerk of Works is to see that the course upon whichthe damp-proof material is laid is carefully flushed upwith mortar to an even bed, and the damp-proofmaterial laid and protected from injury while the mortaris setting.

4 Points for attentionin brickwork

In ensuring that the provisions of the specification withregard to bricklaying workmanship are observed theClerk of Works should pay personal attention to thefollowing:

1 That the correct bricks to match the specifiedcoursing, and metric or imperial, as specified are onthe scaffold.

2 Adequate and correct damp proofing.3 Flushing up of bed joints and filling of collar and

cross joints; bricks frog up.4 Correct brick coursing, with correct course

alignment, and the keeping of true perpends.5 Correct wall ties, correctly set and correctly spaced.6 Proper raking out of joints for subsequent pointing.7 Cleanliness of all cavities and the correct use of

cleaning out holes, and cavity battens.8 Correct cavity gap dimensions.9 Accuracy in dimensions of openings, and adequate

and correct frame fixing.10 Accurate provision of sleeves and chases for

services.

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5 Particular attentionto cavity brickwork

6 Weep holes

7 Closure of cavity

8 Snap headers

9 Mortar mixing

11 Protection of features, finished stair treads, andcast stone work as soon as built.

12 Protection and cleanliness of finished brickwork;including protection from scaffold staining and fromsplashing off scaffold boards (the inner of whichshould be turned back during rain).

With the very much increased use of irregular labour-onlybricklaying gangs, particular attention needs to be paid by theClerk of Works to the regular and proper supervision of allcavity brickwork.Considerable troubles have occurred on sites due to slipshodworkmanship in cavity work; and considerable expense insubsequent repair has been incurred. A Clerk of Works incharge of brickwork must be quite certain, from personalobservation, that in every part of the cavity brickwork there isthe correct wall tie type, correctly positioned, fully beddedonto each leaf, with the correct width of cavity, and positivecavity cleanliness. The Clerk of Works must take immediatesteps to effect a controlling position in this work. This positionshould be taken, with aid from the Superintendent of Works,and from the Job Architect, regardless of objections from thecontractor, or walk-offs by irregular bricklaying gangs or otherdifficulties.Slipshod work in a trade of structural significance suchas bricklaying is such a serious matter, that timely andstrong steps must be taken to see that it does not occurin this department’s work.

If weep holes are not specifically indicated in any type ofcavity work the Clerk of Works should obtaininstructions from the architect-in-charge. It will benormal for weep holes to be left at every fourth verticaljoint in the external wall at the bottom of the cavity, andover openings.

Special attention should be given that the closing of thecavity at sides and head is correct to detail shown ondrawing.

In cavity walls not in stretcher bond ’snap headers’ areoften a source of trouble; care should be taken thatthese are cut neither too long nor too short, and if notparticularly specified the use of purpose-made snapheaders (as distinct from those cut on the scaffold)should be encouraged.

It is a specified requirement that all mortar materials shall beaccurately gauged by gauge by gauge boxes and mechanically mixed.

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10 Point ing

11 Sample brick panels

Particularly with calculated brickwork, the Clerk of Worksmust ensure that the methods the contractor uses forproduction of mortar for the bricklaying gangs does in factproduce, with adequate accuracy, a mortar of the proportionsspecified.Retempering is not permitted.

The finish of brickwork mortar joints may beFlushFlush ironedWeatheredKeyedRecessed

and which one is to be used is specified for each type offacing brick.Where pointing is required this is also specified.

The Contractor should be instructed by the Clerk ofWorks to produce sample panels of brickwork jointedand pointed for the approval of the architect-in-charge.Particular attention should be paid by the Clerk of Worksduring pointing operations subsequently to ensure thatthe approved method, colour and texture, are absolutelymatched and maintained, without any variations betweendifferent portions of the work.

12 Sample loads of bricks The first sample load of bricks that is accepted andapproved by the architect-in-charge should be retained,until completion of all brickwork deliveries to enable thequality and appearance of all subsequent deliveries to bejudged.

13 Brickwork in frostyweather

In cold weather, as a protection against night and earlymorning frosts the Clerk of Works is to see that newlyerected brickwork is properly covered. Stacks of brickson site should also be covered and if the contractoromits this precaution the Clerk of Works should notallow the use of frosted over bricks.

14 Admixtures Contractors are prone to request permission to useadmixtures alone, in the mortar, to protect against frost,rather in the form of a prophylactic.The use of admixtures alone, without special coveringand heating measures, is of very little practical use forthe mortar usually specified.Permission should not therefore be given for loadbearing brickwork to be built in freezing weather, whenthe contractor proposes using admixtures alone.With proper heating and covering measures, however,brickwork can usually proceed, and if the contractor puts up

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detailed proposals for this, thenarchitect-in-charge for approval.

they should be referred to the

15 Examination of Where brickwork has been built in freezing weather thebrickwork built in frost work should be given a special examination by the

Clerk of Works the second day after being built. If thereis no obvious frost damage but the work is suspect,portions should be tested with a blow lamp; if the mortarsoftens frost action has most certainly affected the workwhich must be rebuilt.

16 Sills and thresholds The Clerk of Works should see that continuous sills andthresholds built in as the work proceeds are bedded onlyat the stoolings to prevent fracture at settlement, theopen joint being subsequently filled with mortar.

17 Partition blocks The Clerk of Works is to see that lightweight, clinker,concrete blocks for partitions are given all reasonablepossible protection against rain or frost, are stacked offthe ground, with reasonable facilities for air circulation,and when used in the work are dry and adequatelymatured.

18 Tests during brickwork

19 Flues

The Clerk of Works is to obtain instructions from thearchitect-in-charge relating to the testing of materialsused in brickwork. It will be normal for the followingtests to be carried out:1 Crushing tests for bricks for designated brickwork.2 Porosity tests on facings.3 Strength tests on partition blocks where brands in use

have not been recently tested and given generalapproval.

4 Mortar tests.5 Breaking tests on a percentage of precast concrete

steps.Details of a Clerk of Works duties in connection with theforwarding of samples for testing, to the Council’sTesting Station, are given in the Section of theseinstructions entitled ‘TESTING‘.

Very special attention is to be paid to ensuring that all fluelinings are fixed socket upwards, are properly jointed insulphate resisting mortar as specified and have a solid andcontinuous backing. All flues are to be tested by theContractor in the presence of the Clerk of Works who is toforward a certificate to the department, at the completion ofeach portion of the work that the flues have been tested inaccordance with the specification and found clear. The Clerkof Works should also record the date of the tests in the JobDiary.The Clerk of Works should ensure that flues are cored as

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20 Making good to ductsand other partystructures

21 Records that are to bekept of all cavity andsimilar brickwork

22 Manner in whichrecords are to bekept

23 Cladding panels

2 4 Cracking of brickworkand failures ofbrick cladding

the work proceeds, coring holes being left wherenecessary; coring should not be delayed until thechimney is complete.

The Clerk of Works is to examine the making good ofall holes in ducts, especially under baths, or in similarawkward positions, so that there is no possibility of micegetting into dwellings via ducts or from one dwelling toanother where these are connected to the same duct.Such cases have occurred. If there is any potentialweakness, where such infestation might be likely tooccur, the Clerk of Works is to draw this to the attentionof the architect-in-charge.

It is most important that records of cavity and similarbrickwork completed section by section, and floor byfloor are personally recorded by the Clerk of Works.A record should be made before each sealing of temporarycleaning out holes.This recording indicates that the Clerk of Works is satisfiedthat each section of the brickwork has the specified numberof the correct ties, correctly positioned, fully bedded ontoeach leaf, with the outer leaf (if applicable) correctly ledged onto the concrete nib, with the correct width of cavity andpositive cavity cleanliness, and that the section of the workhas been completed in full accord with good practice and thespecification concerned.

Normally these records will be kept in chart form onelevational drawings (similarly to records of concretepoured) and must be readily available to the architect-in-charge and other inspecting officers.At the commencement of the brickwork on the contract thedetailed supervision of the work, and the manner in whichrecords must be kept are to be discussed by the Clerk ofWorks with the superintendent of works.These instructions apply to all cavity brickwork, includingwhere single skin brickwork is used to clad concretecolumns or walls with anchors to slots being used asthe fixing method.

Where cladding panels are used the Clerk of Works mustmake similar arrangements for the detailed supervision of thepositioning and fixing of each panel, and the method ofrecording this, with the superintendent of works.

During the last ten years there have been a number ofcases of cracking, brick slip damage, spalling, andmovement of half-brick skins to buildings, mainlymulti-storey reinforced concrete framed buildings whereconcrete shrinkage, and creep, are factors, not usually

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involving major structural failure, but involving thedanger of parts of brickwork falling and endangeringthe public below.Some Clerks of Works consider it something of anenigma that these failures of brickwork cladding shouldoccur on work built during the last ten or twelve years,but seemingly not in earlier work. It is a matter forthought, but it could well be that the comparativeflexibility, and fragility, of modern half-brick outer skins,sometimes ledged onto concrete nibs, in contrast toearlier sturdier, if less efficient, designs, demands aprecision of tolerance, and a workmanship accuracy andthoroughness not always forthcoming. It is notunknown that the tying of an outer skin of brickwork bywall-ties or anchors, might be somewhat less thanperfectly carried out by bricklayers working under thestress of modern bonus conditions.Nor has the necessity for appropriate movement joints inhalf-brick cladding been fully appreciated, orincorporated in designs where the risk of differentialexpansion, or shrinkage, is present.These are all points to be noted very seriously by each Clerkof Works, in connection with the designs which have to beworked. Any points of difficulty, or doubt, should bediscussed as necessary with the architect-in-charge.

25 Code of PracticeC.P. 121

The Code of Practice C.P. 121, Part 1, for Walling,published in 1973 should be thoroughly readby each Clerk of Works, in particular the sections on’Methods to reduce the incidence of cracking inbrickwork and blockwork‘. The basic principlescontained in these sections should be studied, andunderstood, by all Clerks of Works.

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12 Stress Grading of Timber

1 Code of Practice This refers to structural timber, as distinct from joineryCP 112 timber. The use of timber structurally is governed by

British Code of Practice CP 112 (1971) and BS 4978which have been prepared primarily for the guidance ofengineers, and it is the department’s structural engineerswho will issue instructions and working rules in thematter, for example timber roof trusses, and the stressgrading, machine or visual, of the timber concerned.

2 Stress Grading Stress grading of timber simply means the assessmentof the strength of the timber, and the reduction in thebasic strength necessary because of defects such asknots, sloping grain, shakes and splits, or other imper-fections and variations that one meets in a naturalmaterial such as timber.

3 Methods of Grading 1 VISUAL GRADINGGraders examine the timber visually guided by AppendixA of Code of Practice CP 112 and the rules laid downin BS 4978, and make their assessment of the timbergrade. This is clearly a most uncertain method,depending on the experience, and the caution, of thegraders, who can vary on occasion, in rejectionfigures, by up to 25%. In addition there are very fewqualified graders in the Country and as a consequencevisual grading is virtually never properly carried out.2 MACHINE GRADINGMachine stress grading measures a relative ’stiffness’and therefore strength, of the timber under test, thestiffness of timber being taken to be a fairly reliableindication of timber strength.This stiffness is measured non-destructively by aComputermatic Stress Grading Machine, the timberpassing through this machine at a fast rate, and depend-ing on the deflection of each section, measured bycomputer, the timber is colour marked indicating itsrelative strength. The strength grade is then the lowestmarking on the length of timber being tested.This is naturally a very much better comparison methodthan the varied visual assessments of the differinggrading personnel.

4 Limitations of Machine Machine stress grading has certain limitations inasmuchStress Grading as there are certain specific defects not revealed by the

machine testing process, and therefore it will benecessary for the Clerk of Works to visually inspectmachine graded timber for compliance with specification

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5 Colour Coding inMachine Grading

requirements in respect of these defects. The defectsconcerned are wormholes, sapwood, fungal decay,brittle heart, bow and twist, fissures, resin pockets andwane. Where of course the reduction of strength causedby the defect is less than that caused by the defectadmitted by the grade of timber then the piece of timberexamined may be accepted.It may be necessary however for the Clerk of Works totake advice from the Structural Engineer on the valuationof these defects and the treatments that may be necessaryto neutralise these defects, pending the issue of rulesfor ’The Visual examination of Machine Stress GradedTimber for Structural Use’ which is to be included inthe Preambles as an Appendix to a new Clause NI.4.

There is no British Standard colour code for machinestress graded timber. BS 4978 states that each piece ofmachine stress graded timber shall be stamped with theBS Kite Mark giving details of grade, licence numberof grading machine, etc.Licensees of the British Standards Institute Kite MarkScheme tend to follow the recommendations givenbelow with regard to colour coding:

M75 Grade—redM50 Grade—blueMSS Grade—purpleMGS Grade—green.

Reject timber is usually unmarked.

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13 Joinery

1 Timber For most of the housing joinery of the Departmentsoftwood is used, the more expensive hardwood beingused in special situations only, and for high quality work;of the softwoods, Baltic Redwood is most often used atthe moment, usually purchased by the joinery manu-facturer in the grade ’unsorted’.

2 Timber windows It is departmental policy that timber windows, inaccordance with Branch details are to be used in alldwellings, except in special cases where express approvalis given for aluminium windows.

3 Quality of timber In late years the quality of timber in softwood joinery offeredby the joinery manufacturers has in very many casesdeteriorated and has not met the full and proper requirementsof the department’s specifications. The Clerk of Works isoften placed in difficulty in this matter, being usually underpressure to accept the joinery as delivered, and thereforeuncertain how to advise the Job Architect on suchacceptance or otherwise. The Clerk of Works must, in everycase, observe the correct procedure, as given later herein forthe proper detailed and thorough inspection of the joinery.

4 Early decay of timber Early breakdown of timber in external joinery has beenexperienced on some Council sites through the rotting ofsapwood.

5 Early occurrence ofwet-rot

6 Moisture

7 Sapwood in softwood

The failures that have occurred have usually been due towet-rot occasioned by sapwood in softwood joinery timberbeing permeated by moisture, the amount of this moisturethat gets into the untreated sapwood, and the readiness withwhich it gets in, in fact determining the life of the joinerycomponent.It is the Clerk of Works duty to take such care in theinspection, installation and protection of joinery, inparticular external softwood joinery, that any such earlydecay does not occur.

It must be reiterated for emphasis, that whiletemperature and moisture control the movementbehaviour of timber, moisture content is the governingfactor in the suitability of timber for building; and thepenetration of moisture into the vulnerable sapwood isthe prime cause of decay.

The sapwood in softwood timber such as Swedish

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Redwood, readily absorbs moisture and has very littleresistance to decay. Nevertheless to take the logicalcourse and to strictly specify that all softwood timberfor external joinery shall be completely free from sapwoodand to have that specification satisfactorily filled, hasnot proved to be commercially practicable.Therefore in joinery for low-cost housing it is necessaryto use softwood, knowing it has a vulnerable sapwoodcontent, which unless treated, and protected, is likely tolead to early decay and breakdown.

8 Sapwood in hardwood When hardwoods in usual use contain sapwood this isperishable, and not only this but both the sapwood andthe heartwood are resistant to treatment withpreservatives. Therefore where hardwoods are chosen forexternal joinery it should be stipulated that the hardwoodshould have no sapwood content, and the Clerk of Worksshould look for this during inspections.

9 Measures to be taken Under circumstances such as these where timberwith softwood in present containing sapwood and having little resistance today use decay has necessarily to be used it is essential:–

1 To increase the resistance to decay artificially; andthis is done by preservative treatment.

2 To accept only timber adequately seasoned and at theappropriate moisture content before being made intojoinery and at time of delivery to site, and3 To maintain the finished joinery at all times at theappropriate moisture content and to fully protect it fromthe ingress of moisture, which means: fully coveredstorage; no open joints; full and complete gluing of alljoints with the right glue; no unprotected end grain;early and effective priming and painting; adequateputty work, paint covered; and, naturally, full andproper maintenance.

10 Preservation It should be noted that British Standard 1186, whichis based on a draft prepared by the British WoodworkManufacturers Association, representing trade interests,makes no mention of preservation, except in so far asthe added notes at the foot of Appendix A, page 11,refer to Code of Practice CP 153.Both the British Standard, and the Code of Practice, areissued on the larger contracts to Clerks of Works and shouldbe studied.Clerks of Works are to note that departmental policynow directs the use of preservation for all externaljoinery (other than ply-faced doors).Preservation for external softwood, is to be by one of thefollowing systems:1 Boron diffusion

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2 Double-vacuum impregnation3 Automatically controlled immersion for a minimum

period of three minutes.

1 1 Moisture contentof joinery as deliveredon site

The moisture content of timber in joinery. duringmanufacture, and when it arrives on site should beapproximately 17% for external joinery andapproximately 15% for internal joinery for buildingswith intermittent heating.The Clerk of Works should check, and record, themoisture content, using a moisture meter, as soon asjoinery arrives on site, as part of the joinery inspectionroutine. A moisture meter is available from the SitesManagers’ Office.

1 2 Maintenance of lowmoisture content

A great deal of responsibility devolves on the Clerk ofWorks to see that joinery. after delivery to site, and untilthe building is handed over to the client’s departmentand taken into service, receives proper protection, bothin storage, and as far as may be possible duringinstallation. so that the moisture content of the timberremains reasonably within the appropriate limits. Underthe arduous conditions on site this will mean constantvigilance on the part of the Clerk of Works to see thatthe joinery is efficiently stored, fully covered andadequately protected at all times.

1 3 Special steps for Special steps may have to be taken in specificationcentrally heated buildings instructions to the main contractor and for his joinery

1 4 Moisture danger limits It is considered that the decay safety limit of air seasonedsoftwood, in equilibrium with its surroundings, for bothdry and wet rot, is a 20% moisture content.

1 5 Examination of joinery The first step for a Clerk of Works is to examine thedrawings and joinery drawings, in particular, window drawings, and tospecification study the specification.

manufacturer for the maturing and kiln drying of timber;and special steps in protective measures may also haveto be taken on site when the joinery is for centrallyheated buildings. or is to be used in constant heatpositions.If the necessary procedures are not dealt with in thespecification then the Clerk of Works should requestinstructions, at the beginning of the contract, from hisarchitect-in-charge.

1 If the windows, for example, are light in section,particularly the opening lights, and are set in sheer faces,without weather protection, then the Clerks of Works must

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16 Sample items of joinery

1 7 Visits to joinery works

be relentless in the inspection knowing that there is nolatitude whatever.If the windows are stout in section with no possibletorsional deformation of opening light, and a solid job set indeep reveals, then the Clerk of Works may not find thework so onerous.

2 Note whether there are any horizontal surfaces, suchas top surfaces of sills or rails that might holdrainwater or condensation and could with advantagebe sloped off to shed such moisture.

3 Note whether condensation channels are shown, andwhether they are drained.

4 Note what capillary channels are shown, and theirsize and shape.

5 Examine the joint details, particularly the main framejoints for possibilities of keeping end grain to aminimum.

6 Check the window/wall joint detail–a rebate in theframe or a lap joint, as appropriate, enables sufficientwidth of mastic to be used. Remember one of thebasic principles about mastic joints–the masticjointing, never permanent for the life of a building,should be accessible and it should be easy ofinspection, and readily replaceable.

7 Check the types of frame joints, if shown, and thetypes of glues specified. Brief yourself as to the correctappearance of the specified glue. Often at a glance itis possible to tell that the wrong glue is used, as sofrequently happens.

It will be normal for a joinery manufacturer to supply sampleitems of important joinery, especially windows, for approvalbefore bulk manufacture is undertaken. The Clerk of Worksshould meticulously examine this sample with the JobArchitect, noting any particular bad features or difficulties, sothat the manufacturer has guidance on the lines on which toproceed.This approval of sample however does not take the placeof inspections and fully detailed joinery inspections of alldelivered joinery must of course take place: andadditionally, a random selected frame, or frames, must besubjected to breakdown examination.

When bulk manufacture of windows and other joinery hascommenced and a first delivery of joinery is nearly ready, theClerk of Works, accompanied by two members of the joineryinspection team from the Sites Manager’s Office, with theJob Architect if s/he so desires, should visit the joinery worksand make a detailed inspection of the joinery which shouldinclude windows.It may be necessary to repeat visits to the joinery works until

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16 Rules for visits toWorks

19 Guidance notes onjoinery inspections

the competence of the joinery manufacturer has been fullyassessed as regards the quality of the products, and toensure that the joinery manufacturer is working along theright lines; thereafter it will usually be appropriate to examinejoinery as it is delivered to site.

When Clerks of Works visit joinery works, or for thatmatter any other works on inspection duties, the partyshould consist of never less than a team of two officers.They should proceed in either Council, public or theirown transport, and meals or similar refreshments are to betaken under the officers’ own arrangements only.Arrangements should be made, even if the joinery worksis some distance away, for the visiting officers toarrive at the works early in the day, normally not laterthan 9 a.m., and leave only when a satisfactory day’sinspection has been carried out. The Sites Manager’soffice will arrange transport where required, and theSite Clerk of Works should notify that office when visitsto works, or site inspections of joinery, are required.

The Joinery Inspection Report form acts as the Clerkof Works or other inspecting officer’s Check fist. Thiscan be obtained from the Sites Manager’s Office, or fromthe Materials Section. A copy of this is included as anAppendix at the end of this section for reference.As priming hides the surface, and therefore many of theimperfections, the joinery must be inspected before it isprimed.In the inspection of joinery with special reference to theitems of external joinery under greatest exposure, such aswindows, a literal interpretation of the specificationwithout the balancing influence of a wide experienceand a knowledge of suitability for purpose would beinadequate, but nevertheless the Clerk of Works mustrealise that there are restrictive limits to the quality ofjoinery that may be accepted by the officers of thisdepartment.The following notes are a guide as to where emphasisis to be placed in inspections of detail:–1 Timber mark should be noted whenever timber in

bulk is being inspected.2 Species of timber should be ascertained from the

manager or buyer of the joinery firm, via the maincontractor as appropriate, so that all parties concernedare fully aware of the potential weaknesses whichthe visiting officers will be discussing.

by meter in3 Moisture content is to be checkedseveral positions and recorded.

4 Preservative treatment is one of our two mostimportant safeguards for external joinery. The methodused, and the method of certification, is to be noted.

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5 Joints: first class workmanship in jointing with fullglue sealing with the correct glue is our secondimportant safeguard, and this without questionmust be checked by the Clerk of Works and otherinspecting officers.If crevices are present these must be filled afterpriming with a white lead oil paste stopping. Con-trary to the impressions of some joiners, nails arenot an acceptable substitute for non-ferrous dowelpins.

6 Glued work: It must be emphasised that gluedwork in joints must be efficiently carried out to beacceptable. The provisions of British Standard 1186and of Code of Practice 153(2) page 9, must beknown by every Clerk of Works in this respect.This is one of the matters that must be given specialattention in the breakdown examination by Quality-Control of a random selected frame.

7 End grain: Thus is particularly vulnerable to theingress of moisture and should be at an absoluteminimum, and fully treated by preservative, and ofcourse later fully protected by a thoroughly wellapplied full bodied primer.

8 General finish and appearance of all joinery workshould be examined and commented upon. It shouldbe noted that British Standard 1186, part 2,’Workmanship in Joinery’ implies that unlessotherwise specified, and these are the operativewords, surfaces of joinery to be painted may not besatisfactory for painting with gloss paint. This willnot do for the department and such surfaces mustbe appropriately rubbed down.

Growth rings and their number per inch givean indication of the speed of growth, the coarsenessof end grain, and the ease or otherwise of thesurface machining of the timber. They are guidancefigures only and only outstanding deviations fromthe specified figures need be noted.

9

10 Slope of grain, which must be limited to avoidpossible warping, depends to some extent naturally,on its use, and experience dictates here, butnormally there should be no difficulty in obtainingat most one in ten, local deviations being ignored.

11 Splits and shakes give any examiner some ideaof the general quality of the timber and its historyof variation in moisture content; splits and shakesshould not be viewed complacently.These timber faults are covered in British Standard 1186,although some consider not very strictly.

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The Clerk of Works should insist on strict compliance withthis as a minimum standard.

12 Pith, i.e., the heart of the log, is not permissible,under any circumstances on exposed faces ofexternal joinery.

13 Blue Stain as an unsightly discolouration should beavoided where possible. Unless dealt with in thespecification it is allowed other than for clear finishwork, by the latest edition, 1971, of BritishStandard 1186.

14 Knots—that are small, sound and tight are, ingeneral, acceptable, particularly in isolation. Theexact guidance knot sizes that are acceptable arespecified in some detail in British Standard 1186of 1971, but the use to which timber is put isimportant, and sensible considerations shouldinvariably prevail. For example sound knots on aninside face are usually immaterial, whereas on anexposed face of the higher classifications of timberonly the occasional tight small knot would bepassed.

15 Plugging in place of knots is of course permissible insensible locations. If a Clerk of Works is in doubt about aknot or series of knots, not in a clear finish surface theposition should be visualised as if a small annular holewas in place of the knot or knots concerned. If such a holewould allow water into the building, or into the internals ofa joint, then plugging in such a position would not be anacceptable solution.The contractor who produces, to meet the higherclassifications of timber, a member which has a cluster orcontinuous line of plugs in place of a number of arris ormargin knots, as has occurred, maintaining that thetimber has ’no knots’ within the meaning of thespecification should be told not to waste time.

16 Decay and Insect Attack are naturally causes ofrejection of the joinery component involved, and ifsuch is found the inspection should not proceedfurther without reference to the architect-in-charge.

The Joinery Inspection Report form should be completedin full. The general principle is that the inspection teamreporting are to supply the architect-in-charge withclear factual information and positive recommendationsfrom which he will be able to make the necessarydecisions and issue instructions for the contractoraccordingly.A copy of the report should not be given by the Clerkof Works to either main contractor, sub-contractor orsupplier. The distribution should be Architect-in-Charge

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20 Earlier Specifications

21 Windows forexamination

breakdown

22 Window Test rigs

23 The Combed Joint

(2). Sites Manager (1). Clerks of Works (1). AR/TC (1),and file (1). This is noted on the Report Form.

Earlier Housing Branch specifications directed that softwoodfor external joinery was to be completely free of sapwood.Although rarely used, up to date versions of thesespecifications are available.When a Clerk of Works has such a specification s/he shouldadvise the Job Architect that the contractor’s manager shouldbe asked what he proposes to do to meet the specifiedrequirements on which he has tendered.

Housing Specifications will normally allow for apercentage of the windows manufactured, or otherespecially important joinery frames, to be subjected torandom selection and breakdown examination, and theClerk of Works should check the number so specified.Where, as in the older specifications none is specified,the Clerk of Works should ascertain from the Architectin charge what the position is to be. Quite often onesuch frame will be all that will be required, as long as itis fully random in selection.Needless to say these windows to be subjected tobreakdown examination are not sample windows suchas may be put up by the joinery manufacturers beforebulk manufacture is commenced, but as part of thedepartment’s quality control process, are fully randomsamples selected by the officers inspecting the joineryfor specific breakdown examination of joints, gluing,fixings, preservation and general quality.

This breakdown examination of selected windows withthe object of detecting the faults and weaknesses thatmay lead to comparatively long term deterioration isseparate from the procedure for obtaining the ’immediateperformance’ figures from either the department’s or themanufacturers window test rigs.It is possible that both controls may however form part ofa future full quality control programme.

This joint is essentially a glued joint and dependsentirely on the efficacy with which the gluing operationis carried out, both in workmanship and glue materials,for its efficiency and dependability.The non-ferrous star dowel usually used is not there totake the place of the glue.This joint has gained a bad reputation, particularlyamongst maintenance officers, simply because sitesupervision staff during construction have allowed to

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pass through, in many cases, an ineffectively gluedjoint. The Clerk of Works must watch for this.

24 G l u e s

25 Notes on priming

26 Hardwood flooringon screeds

2 7 Preservation–Wooden doorsto garages

28 Skir t ings

29 Paint protection ofputties

Animal glues (scotch glue or fish glue) and casein glues(made from milk) fail if subjected to continual wettingand therefore should not be allowed for externaljoinery.Weather and boil-proof glues (WBP), are now usuallyspecified by the Department and are synthetic resinglues to BS 1204. Familiar names commercially areAerodux, Cascophen, etc.

1 Joinery has of course to be inspected before primingtakes place otherwise the timber cannot be seen.Priming therefore cannot normally take place at worksunless it is practicable for the inspecting officer tovisit the works.

2 When priming takes place the joinery should be at,as near as possible, the correct equilibrium moisturecontent and this should be checked by the Clerk ofworks.

3 The Clerk of Works should take samples of the primingfor examination in the Council’s scientific laboratories.

4 Where there is too long a time between the initialpriming and the final painting so that the initialpriming, in the opinion of the Clerk of Works, hasdeteriorated then the work should be re-primed.

5 End grain and surfaces against brickwork or concreteshould have a double coat of full bodied primer.

Wooden flooring, hardwood or otherwise should not be laiduntil the moisture content of the screed has been checked.This is best done by a direct reading hygrometer or possiblyby sample test by a solution of phenolphthalein and the Clerkof Works should ask the architect to arrange for the servicesof the Scientific Branch to make this check.

There have been many cases of wooden doors togarages suffering early decay, particularly in the bottomrail, and it is advisable not to forget that these doorsshould also be treated with preservative in the same wayas other external joinery.

Timber skirtings may often be fixed to walls that havea very high moisture content. The backs of the skirtingsshould have a moisture resistant coating before fixing–at least equal to a coating of full bodied primer.

There have been many cases where water has enteredthrough (cracks) or behind glazing putty. Putties should

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be of a non-hardening type and the painting should beoverlapped on to the glass, but neatly so, in every case.In modern dwellings internal condensation on glass isoften considerable and where there is back puttying theClerk of Works should check with the job Architectwhether drain-away condensation channels and/orinternal chamfering-off of horizontal surfaces of framesshould be required.

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14 Mastic Asphalt Roofing

1 Information necessary It is necessary for every building Clerk of Works in theto all Clerks of Works department:

(i) To be well informed on what is good detailingin asphalt work, and what is bad,

(ii) and, to be knowledgeable about the asphaltspreader’s method of working, and be able toconfidently assess what is good workmanshipon a job, and what is bad.

Asphalting is a specialist trade, but it is a straightforwardtrade, simple and direct in technique. When the veryuncomplicated asphalt operation is clearly understood,the rest, design detailing, general technique, and goodworkmanship, is simply basic building commonsense.

2 Definition of Essentially mastic asphalt is simply a mix of asphalticMastic Asphalt cement and suitably graded aggregates, brought to the

site in solid block form, melted to an appropriatelymolten state and spread, on a dry surface while hot,by means of hand tools, to give a dense durable skinsealing any part of a building e.g. a roof, against theentrance of water. At no time shall molten asphaltexceed 230°C.

3 BRS check on asphaltroofs

The Building Research Station undertook the surveyof a number of flat roofs surfaced with mastic asphalt.It is interesting to note that one third of the total roofsexamined had let water penetrate at one time or anotherand this is especially of interest to the Clerk of Worksin that practically all the failures noted were due toneglecting to follow standard, laid down, recommenda-tions for1 detailing and specifying the work, or2 workmanship in installation, in particular at edges,

skirtings, kerbs, outlets and parapets.A similar examination of asphalted roofs in this depart-ment, in 1972 and early 1973, but carried out on an’as required’ basis, revealed very much the samepattern of fault, and for the same reasons.

4 Successful use of Assuming uniformly good quality asphalt material,Mastic Asphalt the successful use of mastic asphalt depends upon:

1 The base on which the asphalt is to be laid, whichmust be stable, with the surface flush, and withoutgaps of any kinds.

2 The adequacy of the detailing. e.g. skirtings, kerbs,outlets, tuck-ins, flashings etc.

3 Good workmanship.4 Protection of finished asphalt work both in new

building operations or in alteration work.

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5 Approritate inspectionsby Clerk of Works

6 Typical faults

The Clerk of Works must not leave this specialist workentirely to the specialist, without inspecting it as efficiently asthe other major building trades; and the senior Clerk of Workson the site must remember that although this is work onroofs, and perhaps because of that, there is no substitutewhatsoever for going up and giving the work a closeexamination personally.

Typical faults that have occurred, are as follows, givenapproximately in order of frequency of occurrence:

2

Slipshod workmanshipin fixing of woodwoolslabs in preparation ofbase–slabs uneven,corners broken,excessive gaps,insufficient nailing, jointsnot taped, free standingkerbs not detailed.Crazing of asphaltsurface.

3 Skirtings under thickness.

4 Trappedscreeds.

moisture in

5 Asphalt failure atexpansion joints.

6 Serious cracks in asphaltat internal angle fillet.

7 Inadequate chase fortuck-ins.

8 Slipshod workmanshipround cradle bolts orsimilar.

9 Slumping of asphalt turnups.

10 Incorrect fixing offlashing, and trim.

Better site supervision, andmore precise detailing.

Not of the utmost gravity;should have beenobviated by site super-vision insistence onadequate sand rubbing.Check by site supervisionhaving samples cut out forchecking on site.Use screed withminimum water content;completely protect againstwater until sealed byasphalting.Better detailing atexpansion joint.Detailing; free standingkerbs, or similar preventivedetail.Site supervision of chasecutting.Site supervision of metalpriming in advance; sitesupervision of detail work.Check adequate keying tosurface; also havecomposition of asphaltsubjected to analysis–this may be faulty.Site supervision; firmfixing and allowance forexpansion.

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11 Warping of timber deck Site supervision muston which asphalt is to be insist that boarding houselaid protected ; not exposed to

weather for any length oftime (asphalt must bespread on felt underlay).

7 Reflective treatments Where felspar chippings on hot bitumen dressingcompound are not specified, then a suitable reflectivepaint could well be used, and it could be helpful if theClerk of Works check with the architect-in-chargewhether such roof paint could be used to provide anappropriate finish to the job. The Director of Housingdoes not favour the use of chippings.

8 A small working gang, A small gang could consist of, typically:and its tools and Spreader charge handequipment Second spreader

Potman, labourerTipper, labourer.

Tools:Floats (including rounded coving floats and sharpround gutter float)Filleters (with wooden nidgers to get into corners)Spatulas (for vertical or near vertical application)Skirting trowelsCold chiselBoasting chiselHandsawHammerMetal cuttersUnderlay cutting knife.

Equipment:Knee-padsStraight edgeSpirit levelGauges (wooden prepared thicknessing battens)Chalk line and chalkSteel tape.

Plant:Mechanical mixer boiler, orPortable asphalt pot (for small jobs)Hand rollerSievesHand brooms and brushesBuckets.

Materials:Blocks of asphalt (kite marked)

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9 Typical workingoperations

10 The underlay

SandUnderlay feltMetal lathingChippings (as required)Reflective paintAluminium edgingBitumen dressing compound (as required)Metal primer.

The base on which the asphalt is to be laid is checkedand any necessary preparatory work completed.1 The mastic asphalt blocks are broken up and melted

in the pot or mixer-boiler.2 The surface on which the asphalt is to be applied

is brushed clean and dry, underfelt is laid, gaugesare set out about 2 metres apart, of same thickness asthe asphalt to be spread.

3 The melted asphalt is brought by bucket (dusted),tipped at the working position keeping the workingedge hot, and spread evenly by hand float, achievingan even surface when the initial spreading iscompleted, by repeated sweeps of the float. Newsupplies of melted asphalt are spread slightly over theedge of the previous one to keep it soft, and the joinis welded together by float. This overlap jointwelded by float and temporary application of hotmaterial enables join to be formed. Blows are piercedand made good while asphalt is warm.

4 On further coats the joins are staggered ; 150mm forhorizontal work and 75mm in vertical work would beappropriate. All joins must be clean and free fromsand or dust.

5 Graded sand is then rubbed by float (and not justbrushed) into the top surface, unless some otherdefinite treatment is specified. This sand-rubbinggives a matt surface, removes the thin skin of richbitumen, akin to ’ laitance ’ in concrete work, andrestrains the development of the crazing whichdisfigures quite a number of asphalt surfaces.

6 On important roofs white spar, or similar, chippings, inbitumen dressing compound, well rolled by handroller, can be laid to prevent excessive heattransmission through the asphalt membrane, or if thisis not done to dress with reflective paint.

Buildings, sub-structures, bases, all move in somedegree. The use of an ’ isolating membrane ’, or underlayusually of black sheathing felt, is to make sure that thebuilding movement has no effect whatever on thecontinuity and water-tightness of the asphalt skin. TheClerk of Works will see that this is just common sense.

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The Clerk of Works will also see that where vertical or slopingwork is involved, when an underlay is necessary, as it is in thecase of a timber surface, steps must be taken to fasten theunderlay in position; and this is done, on the timber, by cloutheaded felt nails at 150 mm intervals, ready to receive metallathing similarly nailed. The Clerk of Works should note thatan underlay is not necessary on vertical or steeply slopingconcrete or similar surfaces. Timber is a special case as beingsubject to movement.Bitumen sheathing felt underlays avoid ceiling stainingwhich can be caused by leaching of bitumen from blackfelt type of underlay.

11 Overall thickness ofasphalt and number ofcoats

When the total asphalt thickness required has beendetermined by experience of the particular use involved,the number of coats or applications within that thicknessdepends upon the maximum thickness a good spreadercan apply on the various surfaces in flat, sloping, andvertical positions.Where asphalt is laid on steep or vertical surfaces, thefirst coat should be regarded as for adhesive purposesonly, and to form an adequate base for the normalapplications. Usually for roofing work, with which thissection of the Handbook is concerned, two coats,additional to the special adhesive coat, are appropriate.

12 Temporary applicationsof asphalt

It is of interest to note that the asphalt trade isunusual inasmuch as purely temporary applications of themain material, molten asphalt, are used quite considerablyusually simply for heating purposes.1 When mastic asphalt is to be removed hot molten

mastic asphalt is placed upon it and when therequired area is sufficiently hot the mastic over coatis removed and the existing asphalt is cut out.

2 Where the edge of a mastic asphalt layer iscontaminated it is cleaned by a temporary applicationof hot molten asphalt.

3 When asphalt is being joined to asphalt hot moltenasphalt is taken over the edge of the older asphalt,and left long, enough to enable the join to bewelded by float.

4 When solid internal fillets are being formed, adequateheat, and cleanliness, are essential. After the necessarythorough cleaning with a brush, hot molten asphalt isapplied to a length of the intersection, and after ashort time is removed. The warmed and softenedintersection, after being worked with a filleter, toclean and remove a thin layer of the flat asphalt,then has fresh asphalt applied, and formed into therequired solid fillet (two coats).

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13 Detailing

14 Improvements tocertain details

Where no specific detail is shown on drawings; orif required for comparison purposes with details shown,a range of reliable details are shown in Figures 1-19 ofCode of Practice 144, part 4, 1970, a copy of whichshould be in the possession of every building Clerkof Works ; with however the query on details 1 and 2as mentioned below. The list of details are as followsfor ready reference :1 Skirting to brick wall, screeded roof.2 Skirting to concrete wall, screeded roof.3 Skirting and dpc to wall, screeded roof.4 Skirting on free-standing kerb, timber roof.5 Tiled finish, screeded finish.6 Skirting and dpc to wall, insulation boarding.7 Eaves finish gutter flashing.8 Drip apron to roof verge.9 Verge finish with edge trim.10 Concrete kerb finish, wood sill over.11 Finish to metal sill.12 Lining to roof reservoir.13 Finish to kerb as water check.14 Rainwater outlet through parapet.15 Flat roof twin kerb expansion joint.16 Sleeve outlet.17 Cast iron outlet.18 Cast iron pipe through concrete roof.19 Finish round metal standards.

Experience in the department does throw some doubt onthe long term efficacy of the details 1 and 2 of the tuck-inmethod of skirting finish to brick walls and concretewalls.The composition of the asphalt, the shaping of the tuck-in groove, the efficiency or otherwise of the flashing orpointing hold-fasts, or, more probably, the ineffectivenessof the keying to brick or concrete vertical face, may havecontributed to the partial failures that have beenexperienced.This however is being subjected to further research, and theClerk of Works could well contribute to this by very carefulexamination, over as lengthy a period as possible of the detailconcerned, and having a discussion about the detail as usedon the contract with the specialist Technical Officer in asphaltwork, of the Sites Managers’ Group.

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15 Plastering

1 Trueness of theplastering system

2 Thin coat

3 1 in 600 tolerance

4 Quality of workmanshipin plastering

Clause 37 of BS 5492, 1977—Internal Plastering—reads as follows :Two coats of plaster can correct only minorirregularities in the background or small deviation fromline or plumb.Provided, however, that the surface to be plastered isbrought to a fair line, and the ground and linings arefixed to a true and plumb line, then the application of aplaster of the order of 13 mm thick to solid backgrounds,other than concrete, can be expected to produce areasonably smooth and flat surface within the followingtolerances, i.e. the plaster should not show anydeviation of more than 3 mm from a 1800 mmstraight edge placed against it. Plumbness can beachieved only with three-coat work, excluding dubbing,with a thickness of the order of 19 mm.No tolerance can be laid down for plastering of lessthan 13 mm nominal thickness since this will closelyfollow the contour of the background, but with asufficiently true surface of plasterboard or concrete asimilar tolerance may be obtainable.The tolerance for three-coat work on a solid backgroundshould not be inferior to that for two-coat work.’

The British Standard lays down no tolerance for a thincoat, i.e., coat less than 13 mm thick because this coatwill closely follow the contour of the background. Thecode considers that a similar tolerance to that quotedshould be obtained on a sufficiently true surface ofplasterboard or concrete.

While this information, i.e., a general surface toleranceof 1 in 600, (3 mm from a 1800 mm straight edge) is aguide, it should be noted that this in itself does notprovide a completely satisfactory method of specifyingwork since many walls which would comply with thiswould not be acceptable in practice. Nevertheless thestipulation of not more than 3 mm deviation over alength of 1800 mm is in fact a guide to the standard ofsurface workmanship that one can have reason forexpecting.

Quality of the workmanship is most important inplastering work, and the skill of the operatives employed.The Clerk of Works must be particularly vigilant ininspecting the first piece of fully finished work that isdone—this should be inspected with more than usualcare—and endeavour should be made to impress uponthe contractor the standard of quality required.On no account may the contractor be permitted, in defaultof the Clerk of Works immediate inspection of the firstfinished work, to carry on with work below standard;

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nor is it any extenuation that irregularity in surface issometimes difficult to detect until decoration is applied.

5 Sample dwellings

6 Preparation ofbackground forplastering

7 Excessive making goodof plaster

8 Cleanliness in plastering

9 Mixes for plastering

10 Detailed inspection ofplaster work

The Clerk of Works should make it a rule that on eachcontract, by arrangement with the architect-in-chargeand with the contractor, the first dwelling should beprepared as a sample dwelling, first showing the qualityof the plastering work required by the department andthen taken to the final decorating stage to show thestandard of quality required by the department infinishes generally. This sample dwelling may also showplumbing layout if desired.

The Clerk of Works should see that the background isproperly prepared before plastering work is commencedand in particular that brickwork joints are properly rakedout and concrete properly hacked for effective key.Concrete surfaces that are to be plastered should beroughened by hacking as soon as possible after shutteringis removed, unless spatterdash or similar methods arespecified. Where dubbing out is required the Clerk ofWorks is to see that sufficient time is given before theapplication of the first plastering coat to enable thedubbing material to fully dry out.

The need for excessive making good is usually the signof badly organised work and seriously mars the overallquality of finish. The Clerk of Works in the interest ofgood finish should pursue the constant aim of keepingthe necessary making good to an absolute minimum.

Cleanliness is essential in carrying out good plasterwork and the Clerk of Works is to see that adequateprotection is given to finished work, including concretesub-floors where set droppings of plaster, unlesscompletely removed, will cause lifting of floor screeds.The Clerk of Works is to ensure that where sanitaryware is fixed before plastering is commenced, it isprotected by board cover or similar means. The Clerkof Works must not permit droppings in baths, basins orsinks. The Clerk of Works is also to see that CCUs arecovered and protected during plastering work.

The Clerk of Works should see that the plasteringmaterials and plastering mix are correct to the specifica-tion and that in the case of special proprietary materialsthe agreed recommendations and special instructionsof the manufacturers are followed.

When inspecting plaster work the Clerk of Works shouldparticularly examine walls at ceiling line, walls at skirting

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11 Sound insulating quilt

12 Screed forthermoplastic tiles

13 Protection fromweather

14 Temporary lighting

15 Patching

16 Bonding agents

line, internal angles and the maintenance of width atreveals and returns. External angles are always fairlyobvious. General surfaces may need to be examinedagainst a side light and with a straight rule, surfaceroughness being checked by sweeping hand across thesurface.

Where an insulating quilt of glass or rockwool is laid it isthe Clerk of Works responsibility to see that it is turnedup at all edges, that it is completely continuous under thescreed and that no direct bond or contact whatsoever ispermitted between the screed and the structural floor orthe walls, either around the edges or between the lengthof quilt. A few square inches of such direct contactwill affect the insulation value of the whole floor. It isthe Clerk of Works responsibility to see by carefulsupervision that this does not occur.

The Clerk of Works is to obtain an assurance for eachfloor of the block from the thermoplastic tile sub-contractor, before the latter commences laying that thescreed is perfectly acceptable. This assurance should berecorded in the Clerk of Works diary.Regardless of this assurance of acceptability the Clerk ofWorks is in addition to assure personally that the screed istrue and level, free of imperfections and to the standardrequired by the department, including, and this is important,being to the required thickness.

During the plastering operation there must be adequateprotection from the weather. This usually means that thebuilding should be glazed before the plastering iscommenced. If not other protective measures must betaken and the Clerk of Works should see that this isdone.

Plasterers cannot do good work in poor light. Wherenatural lighting is insufficient the Clerk of Works is tosee that adequate temporary electric lighting is provided.

It is good practice to see that the area of work left forsubsequent ’ patching ’ is kept to the absolute minimum.

Considerable attention should be paid by the Clerk of Worksto obtaining an adequate key for plasterwork particularly baserendering work. For particularly important work full hacking isusually specified and contractors sometimes ask whether abonding ’ agent ’ added to the mix may be used in place of thekey. The Clerk of Works should strongly advise the JobArchitect against this.

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17 Preference formechanical key

The use of an additive bonding agent makes supervisiondifficult, as unless a Clerk of Works is with the plasterers allthe time it cannot be certain that the correct bonding agent isused, or in fact that a bonding agent is used at all. If a bondingagent is specified the precise agent approved and usedshould be known to the Clerk of Works who should obtaindetails as to correct method of use from the manufacturersand particularly of the preliminary cleaning of surface to berendered.

On important work, keying to a concrete surface byfull and proper hacking removes laitance and is far andaway the better method and what is more the Clerk ofWorks can very rapidly check at any time whether thework of hacking has been carried out and whether ithas been done properly.

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1 Inspection—general

2 Quality of finishedwork

3 Preparation

4 Dry surfaces

16 Decoration

The Clerk of Works is to ensure that:1 The surfaces to be painted are adequately prepared and

are perfectly dry.2 The types and brands of paints applied are completely

in accordance with the specification and are approvedfor use before painting is commenced.

3 The correct number of coats are applied.4 The standard of skill and workmanship, of cleanliness,

and of general finished appearance are entirelysatisfactory.

The Clerk of Works is not to permit the contractor tocommence painting on a surface, or any piece of work,which is not completely ready, in all respects.

The chief points on which the general quality of thedecorative work can be judged by visual inspection are thefollowing, and the Clerk of Works in the inspections is to takeaccount of all these points:1 Uniformity of finish and colour.2 Uniform and complete obscuration of the ground.3 Freedom from any blemishes, such as runs, sags,

wrinklings, fat edges and starved patches.4 Freedom from tackiness.5 Freedom from conspicuous brush marks or ’ ladders ’.6 General cleanliness, neatness of line, and no

disfigurement of neighbouring surfaces.

Correct preparation of surfaces is all-important bothbefore the first coat is applied, and between coats, andthe Clerk of Works is to see that the provisions of thespecification in this respect are followed in detail.Work must not be covered by paint if this preparationhas been inadequately carried out, and the Clerk ofWorks must not permit painting to proceed under thesecircumstances.

In general, climatic conditions before, during and afterpainting have a most marked effect on the immediatesuccess of the work, and on the subsequent life of thepaint. In particular moisture is a potent danger tosuccessful decoration. For this reason the Clerk ofWorks is to make sure that the building has sufficientlydried out and the surfaces to be painted are free fromdampness before decoration is applied. The Clerk ofWorks should not permit decoration to be applied undervery damp air conditions at the position of the work,and in particular spraying should not be permittedduring or immediately after rain.The Clerk of Works is to ensure that adequate ventilationto rooms is maintained in warm weather.

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5 Faulty materials If in spite of tests of materials, and the use of anapproved paint, during the course of the work thepaint itself appears to be faulty, in colour, consistency,drying time, or quality of finish, the Clerk of Worksshould instruct the contractor to cease that part ofthe work, and inform the architect-in-charge, who willcall in the paint manufacturer, and the department’sPaint Inspector.

6 Number of coats of Successive undercoats should show a gradation in colourpaint leading up to that of the finish, and so that the Clerk of Works

can readily check the number of coats applied, s/he shouldinsist that the variation of shade is sufficiently distinctive toallow such check to be made without difficulty.

7 Cleanliness of finishedpaint work

Apart from the requirement of general cleanliness duringworking, and at the completion of decoration, the Clerkof Works is not to permit soiling of the decorationsthrough later work by other trades, for exampleelectricians, plumbers, and floor layers. If any serioussoiling does occur the Clerk of Works must see that themarks are completely removed, and that the finish coatis re-applied on the whole of the wall area of thesurface concerned.

8 Delivery of paint Only paints delivered in decorated cans, or with thestandard printed label affixed bearing the approvedbrand name, are to be accepted on site ; neither type-written labels nor composite labels are to be accepted.Paints delivered in any other way are to be rejectedby the Clerk of Works, who should report accordinglyto the architect-in-charge, as well as noting the rejectionin the weekly report and diary.Cans must all bear a batch number.

9 Dilution of paints—general

The policy is that paints are to be used exactly asreceived from the makers in accordance with the maker’sinstructions and the addition of thinners, driers, orother material will only be permitted when specificallyrequired by the makers, and the procedure approved bythe architect-in-charge. All Clerks of Works are towork within the terms of this instruction. If the paintsas received from the makers are not completely suitablefor use then the contractor must see that these areremoved from the site and are replaced by paints whichare suitable for use as received.

10 Primers for joinery Priming paints are a case in point where in far toomany instances sampling tests have shown that there hasbeen heavy thinning in the paint kettles. The excuse

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11 Brushes for primingjoinery

12 Paint tests

13 Paint sampling

usually made has been that the priming paint is toothick.In fact primers are at times produced that do appearsomewhat thick, and in cold conditions may offer somegenuine difficulty in application. This may be due toinsufficient stirring when the can is first opened, toolengthy storage, storage in bad conditions, or possiblyincorrect formulation by the makers. If the thickness isdue to insufficient stirring another can newly opened andadequately stirred immediately offers the appropriatesolution. In every other case the correct attitude, andanswer, of the Clerk of Works, is that the manufacturermust supply to the site correctly constituted primersthat are suitable for use direct from the can, in place ofthe too thick material, and that if priming work is toproceed on the site this must be done immediately.

Very often the priming of joinery on site is regarded asan unimportant chore, by the agent, that can be carriedout by any available labourer, using worn out ordiscarded brushes or ’ scrubs ’. The importance of theprotective value of good priming is such that this attitudemust be corrected by the Clerk of Works.Priming should be applied, on site, by a skilled operative.A brush should be used, as the friction of the brush helpsto displace air and to ensure that the paint makesmaximum contact with the surface.A metal bound and cemented brush is preferable, madefrom black bristles, sufficiently stiff to carry heavy paints.A three inch brush might be appropriate for large areasbut nothing larger than a two inch brush should be usedfor door and window frames.

The Clerk of Works is to arrange for tests of paints, fromsuppliers cans, and from kettles, early in the contractand thereafter as may be found advisable or asinstructed by the architect-in-charge.Priming paint is to be tested, and if priming alreadyapplied is suspect scrapings can be tested underinstructions from the architect-in-charge.Details of the Clerk of Works duties in connection withsampling and the forwarding of samples to theScientific Adviser’s paint section are given in the chapterof these instructions entitled ’ TESTING ’. Every batchshould be tested, the different batches being identifiedby the batch number on the bottom of the suppliers’cans.

Routine paint sampling for test is the responsibility of theClerk of Works and the Clerk of Works must not expect

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14 Excessive thinningof paints

15 ’Instant paint testing’

that this may be left to the department’s Paint Inspector,whose duty is advisory.When taking a sample for laboratory examination it isessential to stir the paint thoroughly and to practicallyfill the sample tin. The lid of the tin should be replacedwithout delay and the tin shaken.Standard labels are available and on these all theinformation required (including the brand name in fulldetail) should be entered. Samples of both undercoatand finish should be submitted. Should a sample befound unsatisfactory on laboratory examination, it willnormally be required that an unopened can be submittedfor checking purposes.

As various reports and summaries of paint testing overthe last few years have shown the main irregularityrevealed in sampling from painters kettles on site isoften excessive thinning. This thinning, of course, isusually by liquids of low specific gravity, e.g., the use ofwater excessively in the thinning of emulsion paints.When such thinning occurs the density of the thinnedmixture is lower than it should be for correct use.Therefore by comparing the weights of equal volumes ofthe paint from the kettles with that direct from themakers previously unopened cans the thinning can bereadily detected and the percentage dilution assessed.

Hence by the aid of disposable plastic containers, eachholding an equal volume of paint, and a pair of simplescales, dilution can be detected and assessed immediatelyon the site and in fact, if necessary, at the point oftest sampling. Where excessive thinning is revealed inthis manner, the Clerk of Works can take the necessaryaction immediately and there is no need to wait for theseveral days while paint samples are sent back to theCounty Hall laboratories for test.

16 List of approved brands The department maintains a list of approved brands ofpaints, each identified by its particular brand name.This is a restricted document and is regularly reviewed.When a contractor submits brand names of the paints heproposes to use, these are checked against thedepartment’s approved list and the architect-in-chargeinforms the Clerk of Works of the brands that have beenso approved. No other brands of paint may be used on thecontract unless special approval in advance for thisvariation of brands is given.

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1 General protection

2

3

4

5

Orderliness of site

17 Protection of Finished Workand Protection in Storage

All work completed or partly completed on site, and allbuilding materials or components brought on site by thecontractor for incorporation in the work are thereafter theproperty of the Council. As such the Clerk of Works is to seethat they have the protection required for Council property.Protection of finished work including finished concrete workcarried out early in the contract either by the main contractoror a sub-contractor, must have the Clerk of Works’ constantattention and s/he must see that the main contractor providesor arranges for efficient protection of such work.

The Clerk of Works is to see that the site is kept in anorderly condition, and the contractor should bediscouraged from untidy methods of working and untidydistribution of materials. In particular debris and wastefrom one trade is often permitted to hinder the work of afollowing trade ; this is usually due to ineffectivesupervision by the contractor’s staff. The Clerk of Worksshould, as far as it is practicable, see that the debris ofone trade is removed before the following tradecommences operations.

Waste of materials The Clerk of Works should see that there is no unduewaste of materials on site. If undue waste is takingplace and continues after the contractor has beenwarned, the Clerk of Works should report accordinglyto the architect-in-charge so that the matter may bedealt with at a site meeting, and properly recorded andminuted.

Stonework andPrecast work

Protection of newbrickwork

The Clerk of Works is to see that all stonework andprecast work brought on to the site is stored in a placewhere it is not liable to damage, that until it is built in, itis properly protected, and that after being built in alledges and surfaces are properly cased up for adequateprotection as early as practicable.

The Clerk of Works is to see that no material is stacked,even temporarily, against the external walls of thebuilding, and that no water from uncompleted downpipes or other sources is allowed to discharge against thefinished work.The tops of the wall in newly erected brickwork shouldbe covered during rain to prevent mortar being washedout of the joints ; scaffold boards are adequate for this orother form of cover such as tarpaulin or sacking. Theinner board of any working scaffold should be turned upduring rain to prevent splashing and staining of thebrick face. The Clerk of Works should see that theseprecautions are observed as a regular normal routine.

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6 Protective measuresfor concrete

7 Protection in storage

8 Storage of sanitarygoods

9 Plumbing—Frostprecautions

10 Storage of metalwindows

11 Handling of baths

12 General storage andstacking of baths

The Clerk of Works is to see that newly placed concrete isadequately protected against drying winds, sun, heavy rainand frost, and is not subjected to loads, shocks, vibration ortraffic of any kind until it is properly matured. The Clerk ofWorks should see that the provisions of the specification arestrictly observed in these respects.The surfaces and arrises of finished concrete work must beefficiently protected against staining or damage.

The contractor is responsible under the contract for ensuringthe proper storage and handling of articles supplied under theCouncil’s bulk purchase arrangements; and the Clerk ofWorks is to make quite sure that proper handling, storage andprotection, is given to such articles. It is also necessary thatthe materials and articles supplied by the contractor for use inthe work are properly handled and given the storage andprotection adequate to the material or article in question. TheClerk of Works should make the contract requirements in thisrespect perfectly clear to the contractor. If after warning, acontractor continues to neglect the responsibilities in theserespects, or if there are insufficient storage sheds or coverson site, the Clerk of Works should report such neglect to thearchitect-in-charge to be dealt with at site meeting.

Sanitary goods must be stored under cover, and theClerk of Works must never permit these goods, includingbaths, to remain in the open exposed to the weather.In the case of baths these should normally be stackedvertically tap-hole end downwards, supported on woodbattens, and packed at all enamel points of contact.

Where flats are completed but not yet handed overand very frosty weather occurs the Clerk of Works is toensure that the plumbing system is drained until frostdanger is over.

The Clerk of Works is to ensure that metal windows areproperly stacked on edge on wooden battens, with theopening sections closed and secured. They should notbe stacked on ashes or cinders.

The British Bath Manufacturers’ Association of FlemingHouse, Renfrew Street, Glasgow G3 6TG, issue apamphlet on ’ How to Handle Baths ’ and BritishStandard 1189—Cast Iron Baths, gives good recommend-ations for care of baths.

Baths should be kept under cover, stacked and restedvertically with tap-hole ends supported on woodenbattens, each bath separated from the next by dust

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sheets or polythene sheet.Try to have the baths delivered as near as may bepossible to the time they are installed, keep them dryand do not pack them in straw.A bath can be slid into its recess by moving it on twoslightly greased metal slips.The client, the Director of Housing, will not acceptbaths which have been damaged and have been fakedup in any way, as is mentioned in the section of thishandbook entitled ’ MATERIALS. ’

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1

2

3

4

5

Use of permanent lifts

18 Completed Buildings—Handing Over

To assist progress and supervision in tall blocksnearing the completion stage, where to facilitateconstruction the temporary passenger hoists providedby the contractor have had to be dismantled, thepermanent lifts will be made available subject to certainspecific conditions.The Clerk of Works should note that the lifts may bemade available some two months prior to the proposeddate of block handover, but that before this periodstarts the lifts must be tested and certified by the LiftEngineer as fit for service. This certification will not begiven until all builders work in connection with the liftsis completed, and the defects, or snags, in that particularwork are fully remedied.

Use of electrical wiring At the completion stage when snagging is being carriedout internally to dwellings it is of great assistance tobe able to insert bulbs in the dwellings lighting pointsand use the house lighting system to aid remedialsnagging and inspection, particularly in the dark winterafternoons. It may be possible to obtain clearance for thisto be done, and the Clerk of Works should ask thearchitect-in-charge; it is the practical thing to do.

Minimum Defects atFinal Handover

It is essential that the defects or omissions at the formalhanding-over to the Area Surveyor, or other appropriatereceiving officer, are reduced to the absolute minimum,and the Clerk of Works bears a considerable measure ofresponsibility for this.In order to achieve a smooth transfer with the minimumof difficulty to all concerned the Clerk of Works is toobserve strictly the procedure that is outlined below.

Systematic clearance of Regular detailed inspections and checks by the Clerk ofDefects Works, with verbal instructions to the Contractor, will be

made near the projected date of handover to ensure thatthe rectification of omissions or defects is systematicallytackled by the Contractor, and that there are no majorsnags ahead.

Preliminary officialInspection

Approximately two weeks before the day on which abuilding is to be handed over the Clerk of Works is to:1 Inform the architect-in-charge of the proposed date of

handover.2 Carry out a preliminary official detailed inspection with

the contractor’s agent or foreman. This Preliminary

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6 Formal Handing-overInspection

Inspection is to be carried out in a most thoroughmanner.

3 Record in duplicate all defects noted at this inspectionretaining one copy and handing one copy to theContractor’s agent or foreman with the instructionthat all defects or omissions noted are to be remediedbefore the date of handover.

4 If it becomes apparent that the contractor will nothave remedied all the defects listed at the PreliminaryInspection by the date projected for the FinalHandover, then the Clerk of Works IS to advise thearchitect-in-charge immediately by telephone andrequest that arrangements be made to postpone thedate of the Final Handover. It is to be emphasisedthat the Clerk of Works should on no account advisethe architect-in-charge that the work is ready for FinalHandover until the Clerk of Works has personallyascertained that all the defects listed at the PreliminaryInspection are remedied.

At the appointed date of handover a formal inspectionwill be made by the architect-in-charge, and the AreaSurveyor, or other appropriate officer, with the Clerkof Works in attendance.The Clerk of Works is to list in triplicate, using a pen orball-point, any defects or omissions which are noted asstill remaining. The lists will be signed by the officertaking over the building and by the Clerk of Works. Onecopy wiII be handed to the contractor’s agent immediat-ely, one copy forwarded to the architect-in-charge,and one copy retained by the Clerk of Works.Clearance of defects in lift installations to be certified bylift inspector before hand over of dwellings.

7 Formal notification The architect-in-charge will arrange that copies of theto Contractor of Defects defects list are distributed to all departments concerned,from Formal Handing and that a formal notification is made to the Contractor,over Inspection together with a list of the defects that all such defects

are to be remedied within seven days from the date of theformal inspection. The Clerk of Works will receive a copyof this letter and will check that the work is done.

8 Dilatoriness inRemedying Defects

Contractors are very often dilatory in remedying defects,sometimes due to not having an efficient ’ snagging ’ foremanand an effective methodical ’ snagging ’ procedure,sometimes due to having insufficient of the right sort ofpeople on the work.The Clerk of Works must arrange to maintain quietpressure on the Contractor until all ’ snags ’ right throughthe procedure including the final defects noted at theFormal Handing Over Inspection, are fully completed.

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9 TroublesomeLists

’ Snagging ’ Sometimes it may be found that try as one may there arestill a few troublesome items, stretching back into thePreliminary Official Inspection list that still have notbeen done at the time of the Formal Handing-OverInspection. There is nothing else for it except to ensurethat these are written in to the final defects list of theFormal Handing-Over Inspection. If this is not donethese defects are liable to slip completely through theinspection net, with consequent difficulty later.

10 Timely steps, andpressure, to clear upthe final few defects

As well as these minor difficulties, once the FormalHanding-Over Inspection has taken place tension is veryoften completely relaxed, the remedial labourers disappear,and it is very difficult indeed to get the final small defectscleared up. There is nothing so annoying as this to eitherclients or tenants, and the Clerk of Works must takeenergetic and timely steps to see that this sort of thing doesnot happen invoking the immediate assistance of thearchitect-in-charge if the matter cannot be handledpersonally.

11 Clerk of Worksclearance certificate

As soon as in fact the Contractor has remedied alldefects the Clerk of Works is to forward a certificateto that effect to the architect-in-charge. No certificate ofpractical completion should be issued until either theClerk of Works clearance certificate is received, or thearchitect-in-charge has specifically noted and in fullknowledge excluded the remaining defects.

12 Report on Completions The successful completion and handover of dwellings is to bereported by the Clerk of Works (personally by telephone tothe Sites Manager) on the day of the handover, and thenumber of defects listed is to be given.

13 Transformer Chambers It is essential that the Clerk of Works carries out aninspection of transformer chambers or substations atcompletion, similar to that of dwellings, before handingover to LEB for occupation. No handover to LEB ispermitted until defects have been noted and the usualdefects list made out. The usual inspection must alsobe made by the Clerk of Works at the end of the main-tenance period.

14 Maintenance Surveys At the end of the maintenance period defined in the contract,usually six months, a Maintenance Survey is made by thearchitect-in-charge accompanied by the Clerk of Works and inco-operation with a representative of the Director of Housing.The Clerk of Works concerned will normally be the Clerk ofWorks in charge of the original contract.

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15

16

17 Stopcocks

Recovery of CouncilFencing Materials

Horizontal CentrePivot Windows

At the Survey the Clerk of Works is to make a list on the spotof the items agreed by the architect-in-charge and therepresentative of the Director of Housing as being theresponsibility of the Contractor. The Clerk of Works is to handthe original to the architect-in-charge, a copy to theContractor, a copy to the representative of the Director ofHousing, and is to retain the final copy.When the Contractor has remedied all the defects, within theterms of the contract the Clerk of Works is to certifyaccordingly to the architect-in-charge. It should be noted thatno final certificate will be issued to the Contractor until thecertificate from the Clerk of Works has been received to theeffect that all maintenance defects have been remedied.

It is the Clerk of Works duty to ensure that where a site isenclosed by fencing which is the property of the Council,such fencing is not lost to the Council at the end of thecontract, or, if the Contractor refences with his/her ownmaterials, at the beginning of the contract.Clerks of Works are therefore to inform the local AreaOfficer of the Director of Housing as soon as anyCouncil fencing material is dismantled and ready forcollection on completion of the contract or any part ofthe contract.

It is of the utmost importance that the back flaphinges to the Horizontal Centre Pivot windows shouldmove freely throughout the whole circle of their move-ment. Clerks of Works should examine each of thewindows with special care for any sign of binding ortightness in the knuckle. Any such tendency must beeliminated entirely before work is handed over to theDirector of Housing or other authority.

All stopcocks within dwellings should be readilyaccessible by doors which can easily be opened ; ascrewed duct panel access is inadequate. The Clerkof Works should draw the attention of the architect-in-charge to any stopcock-access that does not conform.

18 Testing of GasInstallation

The Director of Housing will not accept handover ofany dwellings unless the gas installation has been testedby the Gas Board, and a satisfactory report of such atest obtained from the Board by the main contractor.This test report is to be forwarded through the architect-in-charge to the Director of Housing.

19 Cradling Eye Bolts 1 PROVISIONAll blocks of six storeys or over must be provided withbolts for the erection of cradling gear for the purpose of

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repainting. Blocks under six storeys in height must alsobe provided with bolts where it is not possible to leanladders against the facade for the purpose of repainting.Details of the standard cradling bolt, which is to be a directsupply item, are given on Departmental Standard Drawings.

2 TESTINGCradling bolts are to be tested after fixing and before theroof finishings are laid, and for this purpose, SuppliesDepartment has arranged for a firm to carry out thetesting under a special direct payment contract. As eachblock becomes available for test a requisition stating thenumber of bolts to be tested should be issued via theDirect Supply Clerk giving at least two weeks notice ofthe work required.The test certificate should be forwarded to the architectin charge for transmission to the Housing Department athandover of the block.Note that out of a sample of 3,656 eye bolts tested3,619 were satisfactory, and 37 failed, all failures associatedwith the builders’ work in embedding the eyebolts.The testing rig in use for the in-situ testing of eyebolts isoperated hydraulically, and electronically records thetensile load applied to the bolt under test.

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19 Sub-Contractors

1

2

Instructions toSub-contractors

Approval ofSub-contractors

3 NominatedSub-contractors

4 Direct Contractors

5 Direct Supplies

Any official directions on sub-contractor’s work should begiven to the main contractor, as a normal routine, in writtenform. The main contractor will then instruct thesub-contractor accordingly. Where it is on exceptionaloccasion expedient that the Clerk of Works verbally directs asub-contractor it is important that the main contractor beimmediately informed of such verbal direction, so that thecorrect channel of liability is maintained.

A main contractor is not permitted to let work to asub-contractor without the prior approval of the Depart-ment. The Clerk of Works should notify the architect-in-charge where there is any case in which a sub-contractoris employed without such prior approval.

When a sub-contractor is selected or nominated by theCouncil and accepted by the main contractor who thereuponplaces the order with the sub-contractor, the latter for allpractical purposes immediately becomes a sub-contractor ofthe main contractor in the normal sense, and is in every wayto be treated as such by the Clerk of Works: except thatunder the contract there are certain obligations on the Councilwith regard to progress of nominated sub-contract works.

In certain cases the Council may enter into a directcontract covering either supply and erection, or design,supply and erection. The responsibility in this case isdirectly with the Council, and the Clerk of Works is totake very particular care that the work is carried outproperly, and to time, fully meeting the co-ordinatedprogramme of work for the main contract. If there isany failing in this respect the Clerk of Works shouldimmediately inform the architect-in-charge, and alsonote the matter in the Weekly Report.Where drawings are required from a direct contractorthe Clerk of Works must check that such drawings aremade available on site in good and sufficient time. Ifthere is any delay whatsoever in the receipt of suchdrawings the Clerk of Works is to inform the architect-in-charge as well as noting the matter in the WeeklyReport.

The Council may enter into a direct contract for thesupply of certain materials, for example facing bricks,reinforcement in special cases of shortage, or anymaterials under the Bulk Purchase (Direct Supply)Scheme.The responsibility for supply is directly with the Counciland the Clerk of Works is to take great care to ensure

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that the supply is maintained adequately to the require-ments of the main contract. In the circumstances of themain contract being delayed the Clerk of Works is tomake the necessary notifications and take the necessarysteps generally to ensure that materials from directsupplies are not delivered too far in advance of thecontractor’s actual requirements.

6 Work by Outside Work will usually be done on a contract by suchAuthorities outside authorities as the Gas Board, Electricity Board

and G.P.O. for their own main supplies or installations.The Clerk of Works is to see that the contractor affords allreasonable facilities to these authorities, and should makenote on the Weekly Report when they are working on site.

7 Work by Outside In certain cases the Council gives permission to outsideSpecialists specialists for work, such as the installation of a radio relay

system, to be carried out during the progress of the contract.Care must be taken by the Clerk of Works that these classesof operations do not involve excessive cutting away withconsequent making good, and if this occurs, the Clerk ofWorks should report to the architect-in-charge accordingly.

8 Labour-onlySub-contractor

Labour-only sub-contracting has become a most importantfeature of building contracting of late years, so much so infact that sometimes a very small nucleus of key peopledirectly employed by the main contractor are the onlypersonnel on the site, all labour operations being sub-contracted—mostly on a labour-only basis.As the system develops main contractors will developthe management skills to operate this type of sub-contracting more efficiently. There are numerouslabour-only gangs forming, and reforming, someestablishing themselves and some dropping out. Addedto which some parts of the industry are very muchagainst the system and are working for the abolition oflabour only generally. While a serious shortage ofskilled labour exists labour-only subcontracting is likelyto continue. The Clerk of Works should treat theselabour-only sub-contractors, as any other sub-contractor,and should note their names on the Weekly Report,as requiring contractual approval in the usual way.

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20 Materials

1 Material Approvals Where materials are specified as ’ equal to . . . or otherapproved ’ and in other cases where so instructed by thearchitect-in-charge, the contractor will put up samples forapproval. No decision is to be given by the Clerk of Works onthese samples, which are to be referred to the architect-in-charge for approval or otherwise. The Clerk of Works shouldnote the approval or rejection in the Site Diary.Any subsequent variation in the quality of these materials orany specific falling off from the standards required by thespecification of any materials should be reported to thearchitect-in-charge. The Clerk of Works should note thevariation from standard in the Diary and in the Weekly Report.Representative samples of approved articles such asironmongery should be held in the Clerk of Works’ office.A full range of samples of all materials used on a contract ismaintained in the Materials Section which the Clerk of Worksshould visit on occasion to keep fully informed.

2 Major Deliveries

3 Sources of Materials

4 Deliveries of joinery

Major deliveries including bulk deliveries of reinforcingsteel should be notified in the Weekly Report.

The Council has to be satisfied as to the origin of amaterial as well as its apparent quality, and it maysometimes be necessary to call for certificates of origin,The Clerk of Works is to notify the architect-in-chargeof any delivery to the contract that contains material ofdoubtful origin.In cases where the contract requires material to besupplied from a particular source, the Clerk of Worksis to give special attention to each delivery of materialsto ensure that these conform to requirements.In the case of timber care should be taken that timberincluding plywood, bears the markings that may berequired in the specification. In the case of steel orsteelwork the rolling marks and origin should be asrequired in the specification.

Good joinery timber is in short supply, and of necessitytherefore we have to take more and more care that theparcels of joinery we receive in the deliveries to site fullymeet the specification.As soon as a joinery delivery is notified thereforearrangements should be made to have a specialist joineryteam alerted to be ready for a detailed inspection, and astandard Joinery Inspection Report completed for thearchitect-in-charge.Full details of the procedures to be adopted in thismatter are contained in the section entitled JOINERY

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of this Handbook.followed.

These procedures should be strictly

5 Direct Supply— The Council arranges the supply and delivery direct to the siteProcedure of certain articles under the Council’s bulk purchase and

Direct Supply scheme. The complete procedure for thesupply and delivery of these articles is detailed in thespecification or contract bills; and the Clerk of Works is to bethoroughly familiar with this procedure.

6 Direct Supply— Requisition forms for articles supplied are given to theRequisitioning contractor normally with the Order to Commence, and the

contractor is required to complete and forward therequisitions to the Council in duplicate within a specified time.The Clerk of Works is to see that the contractor has therequired forms and deals with them promptly; guidanceshould be given by the Clerk of Works to thecontractor’s Agent in this matter if necessary. Copies ofthe requisitions should be kept by the Clerk of Works forreference.It is particularly important to order samples of articleswhen such are particularly useful—the contractorsometimes omits this.

7 Direct Supply—Deliveries

8 Direct Supply—Quality

On receipt of articles supplied direct the contractor isresponsible for detailed examination and check, and forthe completion and disposal of signed Goods Receivedsheets in accordance with the terms of the specification.The Clerk of Works should ensure that the contractor is fullyaware of the responsibilities and knows that breakages,shortages, or quality deficiencies should be notified on GoodsReceived sheets in the manner, and within the time limit laiddown.

In the event of there being a doubt as to the quality ofarticles supplied direct, the Clerk of Works isimmediately to notify the architect-in-charge who willarrange for an examination of the articles in question.Acceptance by the contractor of delivery of any articlesis by no means deemed to constitute automatic approvalof the article by the architect-in-charge; the latter willmake arrangements for the inspection and approval of thefirst delivery of the articles or for a sample of each classof article. The Clerk of Works is to notify the architect-in-charge of the first deliveries of each type of bulkpurchase direct supply article, so that arrangements forinspection can be made, if the architect-in-charge sodesires. Thereafter the responsibility that the quantityand quality of the articles is correct rests primarily withthe contractor.

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9 Direct Supply—Replacement

10 Direct Supply—Delivery Delays

11 Name Plates

Any replacements required by the contractor, for articlesbroken, damaged, or lost, after delivery must berequisitioned by the contractor on the usual form. Assometimes the few articles missing towards the end of acontract cause a delay out of all proportion to theirvalue, the Clerk of Works can most usefully check thatthe contractor orders any necessary replacementssufficiently early to avoid delay in the work.

The Clerk of Works is to make particular note of the deliverydates required by the contractor on requisitions for all articlessupplied direct. These dates should be forward-noted in theClerk of Works’ diary, and any delay in delivery of thesearticles should be brought to the attention of the architect-in-charge and noted in the regular Weekly Report.It is also necessary for the Clerk of Works to ensure thatdirect supply materials are not delivered too far ahead ofsite requirements. Where necessary the contractor shouldsubmit revised delivery schedules.It is not sufficient for the Clerk of Works to wait until thecontractor is ready to use the articles in the work beforenotification of delivery delay is made, even although thecontractor’s Agent may have left the matter until the lastmoment.In the case of delivery delay difficulties the officer incharge of Direct Supply arrangements at the MaterialsSection is most invaluable, and in fact early liaison withthis officer in the general Direct Supply procedure wouldbe most advantageous.

Name and Indicator plates should be received by theClerk of Works and checked for quantity, quality, andcorrectness of lettering and figures. The Clerk of Worksshould notify the architect-in-charge immediately of anydiscrepancies. The plates should then be handed to thecontractor for use in the work and for the issue of GoodsReceived sheets in the usual way. Particular care isrequired in fixing enamelled plates that crazing does notoccur at screw holes.

12 Standardisation ofDirect SupplyMaterials

It is the intention that the pattern of Direct Supply articles andmaterials be standardised. If materials delivered by a suppliershow a departure from standard the architect-in-charge is tobe informed and instructions sought.

13 Damage to Baths Most of the damage to baths on sites is undoubtedlyoccasioned by the contractor’s failure to properly protectthe baths after installation, and a lot of this is impactdamage.

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Contractors argue constantly that either the damage is tootrivial to bother about, or it was caused by a latentmanufacturing defect, or it can be readily repaired, and in factrepair people are sometimes brought on to a site to repairbaths without the Clerk of Works being aware of it.If this question arises the Clerk of Works should inform thecontractor’s Agent that repairs are not accepted anywhere inthe body of the bath, and that baths will not be accepted athandover if such repairs are attempted.The officer in charge of Direct Supply arrangements in theMaterials Section should then be called in to examine thequestion of triviality of defect or latent manufacturing defects.S/he is skilled in these matters and can offer great assistanceto the site Clerk of Works. It should be noted that a number ofthese so called specialist repairs or ’ touch-ups ’ are simplytemporary and the fault discovers itself under use. The Clerkof Works should therefore maintain the attitude that alldamaged baths to whatever degree must be rejected unlessthe architect-in-charge, advised by the Materials Section, or ifnecessary the Scientific Adviser, permits otherwise.

14 Prevention of ImpactDamage

As impact damage is usually caused by other trades, and veryoften by the plasterer it should be the endeavour to have theplastering, and the clearing up operation completed beforeinstalling the bath.

15 Pads for Feet of Baths It has been found necessary in the past, to reject anumber of cast-iron baths owing to defects occurring inthe glazing. Recent investigations have revealed thatthese defects might, at least in part, have been caused byundue strain and vibration on the foot lugs and the bodyof the bath at the points of attachment of the four feetwhen the bath is pushed into position (an operationnormally found necessary owing to restricted space inthe bathroom). In order to minimise these effects, it hasbeen arranged that deliveries of each of the makes oflow bath currently being supplied for use on newhousing work will be delivered with four rubber padsfor fitting on site between the four feet and the body ofthe bath to serve as a form of shock-absorber. Theoperation is quite simple and involves only the placing ofa pad over each of the four foot lugs prior to bolting onthe feet.

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21 Testing

1 General policy onTesting

2 Site Testing equipment

3 Laboratories atCounty Hall

4 Testing of MasticAsphalt—OutsideLaboratories

Tests on building materials and on parts of the work arenecessary to ensure compliance with the contractrequirements and to maintain throughout the contractthe required quality of materials and workmanship.Any and every material used in building can be subjectedto a test. If there is any doubt in a Clerk of Works’mind on any material, or mixture of materials, referenceshould be made to the architect-in-charge who willinstruct as to whether a test is necessary, and theprocedure that is to be adopted.It is necessary that a prescribed minimum amount oftesting be carried out. The Clerk of Works is responsiblefor ensuring that this testing is carried out, and that alltests are made in good and sufficient time to conform tothe progress requirements of the contract.

For tests on site the supply of equipment will normally beprovided for in the contract and will be the contractor’sresponsibility. The Clerk of Works should ensure thatthis equipment is adequate and in first class order.

1 The Testing Station (Room B35) in the Department ofPlanning and Transportation is very well equippedindeed to carry out strength determinations onstructural materials, e.g., tests on concrete cubes,bricks, steel. etc.; is well informed on the abilitiesand efficiency of the various ready mix concretedepots throughout London and will advise on theapproval of such depots; can test soil samples whereurgently required: and can advise on sampling methodswhere necessary including visiting sites where required.

2 The Scientific Branch in the Director-General’sDepartment is similarly well equipped to carry outinvestigations, analyses and tests of all types ofbuilding materials and components, including paintsand will advise as necessary including visiting sitesas required.

Where a Clerk of Works has reason to believe that asphaltmaterial does not conform to specification or has trouble ofany sort with asphalt either workmanship or material, theClerk of Works should call on the services of an asphaltspecialist from the Sites Manager’s office who will visit thesite and advise.When samples are to be taken of mastic asphalt—1 From material in block form as delivered:

pieces to a total weight of not less than 3 kg are tobe taken in approximately equal amounts from not lessthan 6 blocks selected at random.

2 From a mixer or pot at time of laying: a Sample300 mm x 300 mm x 25 mm thick to be cast in aprepared wooden mould.

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5 Forms to accompanysamples

6 Supervision ofSampling

7 Clerk of WorksRecords

3 After laying: A Sample, not less than 300 mm x300 mm and to full depth of material as laid. Theapplication of heat around the edges of the area tobe sampled is permissible: and the sample should betaken by an asphalter.

When analysis is required this will be done by either ofthe outside laboratories, Messrs Sandberg or MessrsHarry Stanger who will report back to the officer namedon the Form AR. 77 (normally the Job Architect) whichform should accompany the samples.Copies of the report are to be distributed to—1 Main Contractor2 Clerk of Works3 Sites Manager AR/TC/SW4 Materials Architect5 Section file.

The following forms, a specimen of each of which isattached, are to be used as indicated :1 Sample Note and Report TS1:

To accompany all test cubes or samples sent to theTesting Station. The appropriate sizes of samples.and relevant British Standards are listed on theback of this form.

2 Form SB/G6To accompany samples for Scientific Branch,including paint samples.

3 Form AR/23This is a wrap-around label to affix on tin containingpaint samples for laboratory analysis by ScientificBranch.

4 Form AR. 77 for asphalt samples:To accompany all bituminous samples requiringspecific laboratory analysis; this analysis will becarried out by an outside laboratory.

The Clerk of Works should supervise all sampling andshould allot a serial number to each sample for itsidentification.It is most important that all the information required by theform to accompany the sample is given. In particular thename and telephone number of the Clerk of Works mustappear on any form which is sent in; and if the tests requiredare to establish compliance with either the contractdocuments, or a By-law, or a British Standard, the appropriaterequirement should be given.

All tests carried out on site are to be methodicallyrecorded in the Clerk of Works diary with their results.And for tests off site, whenever materials are sent for test(properly packed and labelled, and accompanied by the

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8 Tests on Site

appropriate form properly completed) a diary record isto be made. The result of the test when it is receivedshould also be entered in the diary.The Weekly Report should contain a note of:1 Tests carried out on site and their results.2 Materials sent off site for test.3 Results of laboratory tests.

There is not much of a dividing line as far as the Clerk ofWorks is concerned between the tests usually carried outon sites, inspections on site, and accuracy measurementchecks on sites.The more specific of these which could be listed astests on site are as follows:1 Examination of sand for cleanliness—by hand, and by

field settling test.2 Slump tests.3 Covermeter checks. (See Section 10.42.)4 Moisture content checks, e.g., of joinery.5 Accuracy measurement checks.6 Flue tests (copy of form for record, attached).7 Drain tests8 Paint dilution test by instant paint test method.9 Field weight tests on lightweight screeds.

9 Samples sent from the The usually required off-site testing is as follows:site by Clerks of Works 1 Aggregate, coarse and fine, grading analyses.for test 2 Cement testing—manufacturer’s certificate usually

accepted.3 Mortar testing.4 Concrete cube tests.5 Concrete mix composition—analyses.6 Paint-for laboratory test.7 Bricks-strength, dimensions, and, if required,

porosity.8 Reinforcement—if of doubtful origin.9 Precast concrete components, including paving

slabs.10 Timber window—random selection for breakdown

examination.11 Dampcourse material.

10 Testing schedule At the beginning of the contract the Clerk of Worksshould discuss with the Job Architect the general schemeof testing that is to be carried out on the contract,particularly if there are any special materials orcomponents requiring special attention and which theClerk of Works may need to be briefed upon.Wherever and whenever during the course of the contractthe Clerk of Works has doubts about any material orcomponent, other than those that are covered by the normal

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11 Examination of sand

12 Marine aggregates

13 Slump tests

testing, the Clerk of Works should discussArchitect and suggest appropriate testing.

with the Job

Sand is used in many places and many trades on sitesand it is always appropriate for the Clerk of Works to beable to check on its cleanliness and silt content, in asimple direct way.If the usual hand test, i.e., rubbing some sand betweenthe hands, shows staining, the sand will be suspect andthe Clerk of Works should carry out a silt test as follows:Fill a 200 c.c. measuring jar to 100 c.c. mark with sand,add salt water (one teaspoon of salt per pint of water)to the 150 c.c. mark, shake vigorously and leave tosettle for three hours, when there should not be morethan a 6 c.c. layer of silt (i.e., 6 per cent.) on top. Ifthere is more, a laboratory test should be made.If there is 10 c.c. or more of silt the sand should berejected out of hand.Where a measuring jar is not available a clear glass bottleor jar will suffice; put in 65 mm of loose sand, make upto 90 mm with salt water, shake, settle for three hourswhen the silt layer must not be more than 5 mm.

Aggregates from marine sources shall be used only withthe prior approval of the architect.When ready-mix marine aggregate concrete is being usedon site, the Clerk of Works should make arrangementsto visit the concrete supplier’s depot and supervise thetaking of samples of marine aggregates (both fine andcoarse) for submission to the Testing Station atCounty Hall.When marine aggregates are supplied direct to the site,similar sampling should be carried out.The frequency of sampling should be agreed with thearchitect, the structural engineer and the officer-in-charge of the Testing Station.

The slump test on concrete is one of the most importantto carry out, and to record. The Clerk of Works shouldnote that this is to be carried out correctly by the gangeror chargehand demonstrating the slump, in accordancewith the laid-down drill. (Full details for carrying out thedrill for this test are contained in the document given onpermanent issue to each Clerk of Works.)The practical value of a slump test is as a control checkthat no material change has been made in the watercontent or mix proportions of a concrete mix from thoseof the mix approved for the work at the beginning of theconcreting operation.At the beginning of each day’s concreting operation theClerk of Works is to determine the slump of the approved

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14 Field weight tests onlightweight screeds

1 5 General remarks ondrainage testing

mix proportioned as per specification, with correct watercontent to give a workability suitable to the position inwhich the concrete is being placed. Thereafter on thatday for the same materials and the same or similarconcrete placing operations the slump should remainthe same, and should be checked by the Clerk of Worksat least once in the morning and once in the afternoonor whenever the concrete might appear to be varying. Aslump test is also to be carried out at the time concretecube samples are taken, and is to be carried out at eachdelivery of ready-mixed concrete.All results are to be recorded in the Clerk of Works’ diary, anda shear slump is to be noted as such.

The weight per cubic foot is the most important control factorfor a lightweight roof screed and it is important that this beknown while the sub-contractor laying the screed is still onthe site. For this reason the Clerk of Works is to take a cubefrom the lightweight screed at an early stage, weigh it at 24hours old, to the nearest ounce, calculate the density in lb.per cubic foot, check this against contract requirements andnotify this figure on the Weekly Report.

Drains are to be tested by the contractor, who will provide alltesting apparatus, in the presence of the Clerk of Works andthe Environmental Health Officer who must both be satisfiedthat the drains pass all tests demanded by the LocalAuthority.Drainpipes should be water-tested from manhole tomanhole at a test pressure of 1500 mm head of water atthe highest point of a section under test, and the waterpressure must be maintained for not less than ten minutes.Tests should be applied before the pipes are haunchedwith concrete or covered in, and repeated after backfillingthe trench or heading.Subsidence of test water may be due to one or more ofthe following causes :1 Absorption by pipes and joints.2 Sweating of pipes or joints.3 Leakage at joints or from defective pipes.4 Trapped air.Allowance should be made for absorption by addingwater until absorption has ceased when the test propershould commence.Any leakage will be visible and the defective part shouldbe cut out and made good. A slight amount of sweating,which is uniform, may be overlooked, but excessivesweating from a particular pipe or joint should be watchedfor and taken as indicating a defect to be made good.Except where a test is specified it will be usual to test any

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surface water drains that may be constructed of’seconds’ by simply filling the drain with water andnoting that all joints are sound and that no pipes arefractured. The stringency of the test required will usuallybe determined by Local Authority requirements.Tests by ball or mirror and lamp for straightness andobstruction may be required by the Local Authority andshould be applied where possible.Testing by smoke is not adequate for undergrounddrainage.Manholes should be tested for water tightness by fillingthem with water and observing any subsidence of waterlevel.The Clerk of Works is to record in detail in the diary all tests ofdrains during construction and at the completion of thecontract.Before completion of a contract the Clerk of Works is toensure by rodding that all drains are clear and free fromobstructions and all drains are to be tested for soundnessimmediately prior to handing over.

16 Pile Tests note Selected piles will normally be load tested underinstructions from the Structural Engineer, and inaccordance with the piling specification, and therequirements of the District Surveyor. The pilingcontractor will carry out the test and the Clerk of Worksis to make note that the tests have been carried out, inhis Weekly Report and in his Special Pile Driving Record.

17 General remarks onpaint testing

As additional to the ’Instant Paint Testing’ for dilutionreferred to in the section on DECORATION, and in addition tosampling work undertaken as occasion demands by theScientific Branch by direct site sampling, or through the PaintInspector, the Clerk of Works must carry out a personalprogramme of sampling of paints in accordance with theinstructions from the architect-in-charge.At delivery of paint, and on confirmatory instructionfrom the architect-in-charge, the Clerk of Works ispersonally to send up for test a sample direct from themanufacturer’s tins of each type of paint; primer,undercoat, and finishing coat. Each separate batch ofpaint is to be tested, i.e., each delivery bearing a differentbatch number. Batch numbers are marked on the bottomof the cans.During the course of the work, at least twice as a routine,and on any occasion when the quality of the paintbeing applied is at all in question, the Clerk of Works ispersonally to take, and send up for test, samples of eachtype direct from the painters’ kettles.When taking a sample for laboratory examination it isessential to stir the paint thoroughly and nearly to fill the

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18 Tests on flues

19 Testing of bricks

sample tin. The lid of the sample tin should be replacedwithout delay and the tin shaken. Standard labels are availableand on them all the information required (including the brandname in full detail) should be entered. Samples of bothundercoat and finish should be submitted. Should a samplebe found unsatisfactory on laboratory examination, it willnormally be required that an unopened can be submitted forchecking purposes. Paint samples are to be forwarded to theSurface Coatings Section of Scientific Branch, Room 638, TheCounty Hall, in a perfectly clean container filled within 3 mmof the top, adequately labelled, and with the lid firmly fixed,and accompanied by Form SB.96 properly completed by theClerk of Works.

If upon examination difficulty is found in stirring anypaint delivered to the site the Clerk of Works shouldreport to the architect-in-charge immediately.It should be noted by the Clerk of Works that no additionexcept by the paint manufacturer, of thinners, driers orother materials is permitted, and that therefore siteadditions or dilutions by the contractor are expresslyforbidden.The BS covering the paint, as stated in the specification.is to be noted by the Clerk of Works on Form SB.96accompanying the sample.

All flues are to be tested by the contractor in the presence ofthe Clerk of Works who is to note the test in the diary andforward a certificate to the department at the completion ofeach portion of the work, that the flues have been tested inaccordance with the specification and found clear.

Special load-bearing bricks will be tested. Facing bricksmay require to be tested for porosity, and instructionsaccordingly will be issued by the architect-in-charge.Sample bricks should be taken from a stack or sampleload by moving the top two courses in the stack to opena ’trench’ enabling bricks to be taken from the thirdand fourth courses below the top. For the initial testfigures 15 bricks will be taken at regular intervals fromthe third and fourth courses and from each side of thestack. The Clerk of Works is personally to see that the 15bricks are taken as indicated and forwarded to the CouncilTesting Station, accompanied by Form TS/1 properlycompleted and giving the required crushing strengthwhere applicable, against the item ’purpose for whichmaterials are to be used‘.Subsequent check tests should be arranged on brickseach time bricks from a new firing are delivered to the

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20 Testing of slates

21 Cement testing

22 Testing of reinforcement

site, or if it is noticed that there is any variation intexture, colour, soundness, or weight, in any of thedeliveries.

When slates require testing, on instructions from thearchitect-in-charge, the Clerk of Works is to arrange forsix to be forwarded to the Council Testing Stationaccompanied by Form TS/1 properly completed, givinga precise description of the test required. In the case ofdampcourse slates absorption, crushing, and densitytests are required; and in the case of roofing slatesabsorption and density tests are required. In the lattercase the pitch of the roof is to be stated.

Routine tests on every consignment are not normallynecessary. If special circumstances, such as sitedeterioration, make testing desirable, then the Clerk ofWorks is to notify the architect-in-charge accordingly,and make arrangements for test.Otherwise the architect-in-charge will issue instructionsfor the testing of cement during the course of thecontract. For testing, a 5.0 kg sample should be to bedispatched to the Council Testing Station in an airtighttin; the cement should be well shaken down, the tincompletely filled, and the lid sealed down by adhesivemanila paper, labelled, dated, and signed by the Clerk ofWorks. Form TS/1 properly completed by the Clerk ofWorks is to accompany the sample.Tins and manila tape will be supplied by the Department.

Steel either for reinforcement or otherwise, particularlysteel of doubtful origin, may be subjected to test oninstruction from the architect-in-charge in consultationwith the structural or consulting engineer, if so required.When such tests are required, the architect-in-charge willsay what samples are required and give instructions fordelivery to GLC Testing Station. Samples should beaccompanied by form TS/1, on the reverse side of whichis given the size of samples, etc., to be taken.

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107

GLC Testing Station and Soil Mechanics LaboratoryRoom 635 The County Hall London SE1 7PB telephone 01-633 6195

GLC STANDARD SAMPLING METHODS FOR CONSTRUCTION MATERIALS

C O N C R E T E

S A M P L I N GSampling-During discharge of a load from mixer ortruck take a sample of at least 50 kg.

Fill buckets at and of discharge. Place thebucket to collect the whole stream. Alternatively use ascoop.

Combine the four portions and well mix.

C U B E M A K I N GCube making-Fill the 150 mm mould in three layers.

tamp each layer at least 35 times with a steel rammer38 cm long, 25 mm square, alternatively vibrate. Sealtop of wet cube with plastic.

Store at 20ºC for 1 day.

Demould and send to Testing Station.

Keep cube wet

O T H E R M A T E R I A L

A G G R E G A T E

From a load of not more than 10 tonne take a sample of at least 25 kg of coarse aggregate or 13 kg of fineaggregate, Take 10 portions from different parts of the load and combine to form the sample.

B R I C KFrom a load of not more than 10,000 bricks take a sampleof 20 bricksDivide the load into 10 equal parts and take 2 bricksfrom each part.

B L O C KFrom a load of not more than 1000 blocks take asample of 20 blocks.Divide the load into 10 equal parts and take 2 blocksfrom each part.

Avoid taking blocks from the weathered outside of a stack.

FLAGFrom not more than 2000 flags take a sample of 3 flags.Take each flag from a different part of the stack.Record cast date on Sample Note.

B A RFrom not more than 45 tonne take at random 5 bars.

KERBFrom not more than 1000 m run take a sample of 3 kerbs.Take each kerb from a different part of the stack.Record cast date on Sample Note.

R O A D A S P H A L TFrom a load of not more than 20 tonne take a sample ofat least 25 kg.

From each bar cut a specimen 60 cm long.Allow lorry to discharge half its load into the paverhopper, then back off. Take 6 portions from the face ofthe asphalt in the hopper and combine the portions.Send all the sample for test.

If larger samples are required take more portions or units.Consult the Testing Station about methods of sampling soil and materials not here described.

(P.8383)

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109

110

22 lndustrialised Buildings

1

2

3

General

lndustrialisation

Tolerances

A number of industrialised building methods or systems havebeen used by the Greater London Council, and a Clerk ofWorks must be ready to supervise this type of work as wellas traditional work.A considerable number of blocks of dwellings have beenbuilt by industrialised methods, and considerabledevelopment was in hand in the mid-sixties when,understandably the Ronan Point disaster of 16 May 1968caused a considerable check and general slowing downto this type of development. The disaster at Ronan Pointdesigned on the Larsen Nielsen system, was triggered offby a domestic gas explosion on the eighteenth floor andinvolved the progressive collapse of part of a multi-storeyblock of flats, with some loss of life. An official enquiryreported with recommendations in October 1968 andwas followed by numerous searching technical analysesof design and construction methods, and later aconsiderable programme of re-design, and remedial andstrengthening works to all existing similar blocks.

lndustrialised building can broadly be defined as buildingconstruction using large factory-produced and finishedpanel units, usually of reinforced concrete, the basicconstruction method on site being erection or assemblyrather than building. The term ’industrialisation’ coversdesign factory manufacture, co-ordinated deliveries anderection to precise programmes.There is constant development taking place inindustrialised building, and the trend appears to betowards :1 Increasing sophistication of methods of production for

panel units.2 The maximum of finish being applied at the factory.3 Increasing production accuracy.4 An improvement in the quality of workmanship as an

automatic consequence of the increase in productionaccuracy: a matter of considerable importance to theClerk of Works.

There are very many industrialised building ’systems’ inthe industry, varying from systems based on highlymechanised, large, permanent factories through sitefactories to systems which are simply a rationalisation ofthe normal building method.The inspection requirements and methods of the Clerk ofWorks will vary to some extent depending on themethod of production and the type of factory.

The Clerk of Works must be aware of the manufacturing anderection tolerances relating to the site, so that in case of anydifficulty the Clerk of Works is capable of checking in detail

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4 Making good

5 The Clerk of Works infuture development

the appropriate dimensionsunder examination.

of the particular component

The engineering specification will set out in detail principlesfor the acceptance or rejection of panel units or othercomponents that have suffered damage, e.g., damage to ajoint edge. It will also indicate whether in fact making goodmay take place on site or not, and give some measure of theallowable amount of such making good. The Clerks of Worksshould ensure that they are in possession of this type ofspecification, and if not should refer to the architect-in-charge.Any cracking that might occur in a panel unit either before orafter erection, as distinct from minor edge, corner, or surfacedamage, must be regarded seriously and in each case thestructural engineer’s attention must be called to the matter,and the architect-in-charge informed.The architectural specification will detail the surface finishesto units required, and in the matter of damage to these unitswill set the principles of acceptance, or otherwise, for suchunits, and indicate whether the surface finish may be repairedon the site or not. In any case of a quality imperfectionreference should be made to the architect-in-charge. Whenrepair on site is undertaken, it will be the responsibility of theClerk of Works properly to assess whether the quality of themaking good is completely acceptable. If there is any doubtthe Clerk of Works should bring the matter to the attention ofthe architect-in-charge upon the next visit to the site.

At all times it is necessary, and advisable, for Clerks ofWorks to keep themselves abreast of the latest moderndevelopments. particularly at a time when the limitedbuilding labour force of the country is so heavilyoverloaded.

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1

2

3

Assistants undertraining by Clerks ofWorks

Training by experience— Normally the training of junior Clerk of Works acting asClerks of Works—in assistant will include all. or the majority of, the following :course of duty 1 Three months on a commencing contract with

Study by Clerks ofWorks—for personalqualifications

23 Training and the Supply ofTechnical Information toClerks of Works

It is necessary to see that newly joined junior Clerks ofWorks are not only familiar with GLC normal routinebut are given early experience of all types of contractand appropriate technical training so that they mayadequately and confidently supervise any and everyoperation. Senior Clerks of Works should have this inmind when instructing their junior assistants undertraining.

standard foundations.2 Concrete course at Cement and Concrete Association,

Wexham Springs.3 Three months on a contract with piled foundations.4 Short surveying refresher course.5 Three months on a contract which has tall buildings

in the structural stage.6 Timber course at the Timber Research and

Development Association laboratories.7 Three months on finishes to buildings and handover

of completed buildings.8 Short course of lectures on paintwork and paint

testing. These may be followed by a period oncontracts involving one of the processes ofindustrialised building.

The assistant under training will also be expected to follow asuitable course of study which will not only fit the personcompletely for the job, but also lead to some qualificationappropriate to the position of Clerk of Works, e.g., OrdinaryNational Certificate; Higher National Certificate (precededusually by a General Construction Course); ConstructionTechnicians Course; a course of studies leading tomembership of the Institute of Builders or a course of studydesigned to qualify for membership of the Institute of Clerksof Works, by examination.A suitable qualification appropriate to the position ofClerk of Works has become of increasing importance oflate years in the industry as a whole and it may well bethat established Clerks of Works may wish to availthemselves of the opportunities to study for suchqualification.Under certain circumstances time off for day studies maybe granted by the Council, and it may also be possiblefor the expenses in connection with any approved courseof study to be paid. Applications for day leaves or coursepayments should be made to the Establishment Officergiving all the necessary details of the studies to be

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undertaken, when the Establishment Officer will indicatewhether day leaves or course payments are possible.Clerks of Works will need to make their own completearrangements for these study courses leading to personalqualifications.

4 Courses for Clerks of It will be the normal procedure for each Clerk of Works inWorks arranged by the the Department, Senior and Junior, to take at some stageDepartment the following courses, with follow up courses as required.

These will be arranged by the Department, and theClerks of Works will attend under departmentalinstructions :1 Concrete construction course for G.F.‘s and Clerks of

Works at the Cement and Concrete Association.2 Short surveying refresher course.3 Short theodolite course.4 Timber course either at Timber Research andDevelopment Association, or at the D of E. PrincesRisborough Laboratory.5 Short course on painting (Organised via LocalSchool of Building and/or Technical Colleges).It should be noted that when assigned to any courseobligatory for the Clerk of Works to attend, and anyabsence, except by prior arrangement, has to be thesubject of a note to the Establishment Officer.

5 Initial issues of Each Clerk of Works in charge of a contract will betechnical information to issued with :Clerks of Works

1 GLC Architects’ Department Clerk of Works Handbook.2 Permanent issue set of selected British Standards on

selected contracts (as listed below).3 Permanent issue set of selected Codes of Practice on

selected contracts (as listed below).4 Permanent issue set of Building Research Digests on

selected contracts (as listed below).5 London Building Acts Constructional By-laws with

explanatory memorandum—applicable to the InnerLondon Boroughs.

6 The Building Regulations 1976, applicable to allareas of England and Wales except Inner London.

7 By-laws of the Metropolitan Water Board.8 The Drainage By-laws, applicable to the Inner

London Boroughs.9 The Means of Escape Regulations applicable to the

Inner London Boroughs.10 Book of Standard Patterns for colour matching.11 Set of ’Man on the job’ pamphlets relating to

concrete work in the field. (C. & C.A.)12 Metric Information Handbook.

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13 Concrete Practice Pt. I. Materials and Workmanship(C & CA).

14 Concrete Practice Pt. II. Site Supervision and Testing(C & CA).

6 Permanent issue BS NoSet of BRITISH 65STANDARDS for 187Clerks of Works 340

416

437

TITLEVitrified clay pipes, fittings and jointsCalcium silicate (sandlime and flintlime) bricksPrecast concrete kerbs, channels, edgings andquadrantsCast iron spigot and socket soil, waste andventilating pipes and fittingsCast iron spigot and socket drainpipes andfittings

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4471: Pt 1

45514721472949785328

5268: Pt 5

5492560658725973

61506262

7 Permanent Issue Set of CP NoCODES OF PRACTICE 101for Clerks of Works

102

112: Pt 2121: Pt 1144: Pt 4151: Pt 1

153: Pt 2

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Dimensions for softwood (sawn and planedtimber)Testing mortars, screeds and plastersReady-mixed building mortarsShapes and dimensions of special bricksTimber grades for structural useSpecifying concrete, including ready-mixedconcretePreservative treatments for constructionaltimberInternal plasteringAccuracy in buildingLocks and latches for doors in buildingsAccess and working scaffolds and specialscaffold structures in steelPainting of buildingsGlazing of buildings

TITLEFoundations and substructures fornon-industrial buildings of not more than fourstoreysProtection of buildings against water from thegroundStructural use of timberWalling—Brick and block masonryRoof coverings—Mastic asphaltDoors and windows including frames andlinings—Wooden doorsWindows and rooflights—durability andmaintenanceBuilding drainage

8 Periodical Information BRS Digests, Technical notes, instructions, addenda, andamendments will be issued from time to time for insertion inthe Clerk of Works Handbook, and amendments and addendawill also be issued for the other documents held by Clerks ofWorks.It is the Clerk of Works responsibility to see that theseare kept up to date. It is not the intention to issue toClerks of Works codes, standards or brochures which inthe main are concerned with design, or any that areunnecessary for work on site, but there is a mass ofinformation produced each year for the building industry,and if any Clerk of Works desires information on anyspecial subject this can be produced by the SitesManagers office for loan to the Clerk of Works concerned

9 Students and Trainee At times a student or trainee may be attached to the office ofAttachments a Clerk of Works on a Council site. The object is that the

student or trainee should gain knowledge, or improve existing

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knowledge, of practical building constructions.Works should assist towards this end.

The Clerk of

10 Suitable jobs forstudents or trainees

11 Planning usefulattachments

Although the student or trainee can assume no officialresponsibility, an attachment is of much reduced value andinterest when s/he does no work. The Clerk of Works incharge should therefore give the student specific jobs to do,some of which will be similar to those carried out by anassistant Clerk of Works. Students and trainees will be ofvariable ability and experience, and the jobs given should bewithin their competence.

Some maintain that the way to learn about building isto get behind the mixer with a shovel and similarlylabour at other trades. This is considered wrong. Astudent in training should not waste time practisingwork that is carried out by operatives, nor attempt tolearn a craftsman’s skills. Suitable jobs where a studentcan with advantage participate, in short attachmentsto sites are:1 Checking the contractors grid levels of a site.2 Checking the contractors setting out of the main site

and one or two individual blocks.3 Study of the overall construction method—and this

is probably the most important item of all.4 Attendance at site meetings.5 Accuracy check measurements of vital dimensions and

tolerances.6 Engaging in ’snagging’ which means the detailed

examination of work to ascertain defects or omissions,and the assessment of quality.

7 Following up snagging to see how and what thecontractor does to remedy errors.

8 Preparing progress statements for site meetings.

A series of short planned visits to a site or sites are moreadvantageous to a student than long continuous a.m. to p.m.sessions for several weeks; and the architect-in-charge of theproject, when being asked to agree to student attachmentscould well be asked to give guidance on the planning of aprogramme of visits to enable the student or students to gainthe maximum advantage.It may be appropriate that students should carry outattachments in pairs.

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1

2

3

General Co-ordination

Structural Engineer

Housing Engineer

4 Quantity Surveyor

24 Relations with otherDepartments and Branches

The Clerk of Works is to see that officers of otherdepartments and branches are afforded all necessaryfacilities to enable them to carry out their duties, and thatthere is proper and full co-ordination with these officers in allmatters relating to the contract. The Clerk of Works shouldnote in the diary and Weekly Report the visits of the officersconcerned and any decisions that may have been takenaffecting the works.

When the structural engineer inspects foundations orstructural work, the Clerk of Works should see that the workis fully prepared beforehand for inspection, including readymeans of access to deep foundations, and should attend onthe structural engineer during the inspection.If a Clerk of Works has ’Designed-mix’ concretes on thework then particularly close liaison with the structuralengineer is necessary as records of control test cubes may berequired for statistical control and it is probable that thestructural engineer would appreciate the Clerk of Works’assistance here.Similarly where concrete is supplied by the ready mixmethod, even if not particularly designated as a designedmix, a tight control on the ready mix supply is necessaryand a close liaison with the structural engineer is mostappropriate. Additionally where a mix is specified as anominal mix and is being produced on site, it must beproportioned by weight and the weight of theaggregates should be agreed with the structuralengineer.Reference should of course be made to the structuralengineer in all cases where special measures forconcreting in cold weather are to be used for structuralwork.In the general matter of liaison with the structural engineerthe Clerk of Works should be familiar with the section of thisHandbook entitled ’Concrete and Reinforced Concrete’ aswell as the detailed provisions of the specification.

An officer of the Housing Engineers division may carryout routine visits to inspect roads and sewer works onhousing developments.Any observations that may effect adjustments to theworks should be noted for the information of thearchitect-in-charge; and the visiting officers advicesought on any matter that may assist the Clerk of Works.

The Clerk of Works is required to assist the QuantitySurveyor by obtaining and recording any particulars that

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officer may need in connectionadjustment of variations.

with valuations of

5 District Surveyor The District Surveyor’s organisation, a body of highlytrained and skilled professional officers, believed to bewithout parallel in any other city in the world, has thetask of ensuring that all building structures in the InnerLondon area, other than those specifically exempt andsubject to other control, are built strictly in accordancewith the London Building Act and By-Laws made inconsequence of that Act.The District Surveyor amongst other things:1 Discusses preliminary building proposals with

developers, including this Department.2 Carries out surveys of dangerous structures and serves

appropriate notices.3 Examines structural calculations and design details of

proposed developments.4 Advises upon waivers; and5 Inspects the construction work, including foundations,

from time to time to check that all work subject to theLondon Building Act and By-Laws is carried out ’in aproper and workmanlike manner’ to his satisfaction,

The District Surveyor has considerable powers. If abuilder does work which is not in accordance with theAct and By-Laws then a District Surveyor can serve a48-hour notice of what must be done to correct thework, and in the final analysis ask the Courts to fine thebuilder concerned.

6 Relationships between It will be seen that the aims of the Clerk of Works and ofDistrict Surveyor and the District Surveyor are coincidental in that they bothClerk of Works want ’work carried out in a proper and workmanlike

manner’. The Clerk of Works therefore has a very powerfulally and he should treat the District Surveyor as such.It should be noted that the District Surveyor does not officiallyneed to pass any instructions through the Clerk of Works, noras far as the London Building Act is concerned need there beany communication at all, the District Surveyor will instructthe builder direct, and may or may not contact the Clerk ofWorks.Nevertheless the Clerk of Works must carefully attend on theDistrict Surveyor or the deputy or assistant whenever any ofthese officers visit the site, and must make a note of anyinstructions any of these officers give to the builder, or to theClerk of Works. The Clerk of Works should inform thearchitect-in-charge by telephone of any especially importantinstructions given, and also make the appropriate note in thediary.

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7 Mutual Confidencebetween Clerk ofWorks and DistrictSurveyor

A feeling of mutual confidence between the DistrictSurveyor and the Clerk of Works is a most valuablething, and will make a good structural contract so mucheasier to achieve. It is essential, in the case of remedialmeasures or alterations affecting any interferencewhatsoever with structural work, that the DistrictSurveyor be informed immediately the need for this workbecomes apparent.This applies to all alterations or remedial works affectingstructural work, including the cutting back of a ’proud’concrete face, cutting out of any honeycombed concrete,pulling down of faulty structural brickwork and similarmeasures. The architect-in-charge must also be made awareof such alterations or remedial works so that if it is desirable,the architect may discuss the matter with the DistrictSurveyor, or have the structural engineer do so, before thework is put in hand. Either way the Clerk of Works should bevery sure that the District Surveyor is confident of being keptfully and immediately informed of all structural matters thatoccur on the contract. The Clerk of Works must ensure thatsuch confidence is never misplaced.

8 Aesthetic considerations It might be noted that the District Surveyor’s concern is forstructural matters and s/he is not unduly concerned withaesthetics. The architect-in-charge has a large over-ridinginterest and concern in aesthetic as well as in structuralmatters and, naturally, the Clerk of Works has a similarconcern in both fields.

9 EnvironmentalHealth Officer

The Clerk of Works should record in the diary the date of theEnvironmental Health Officer’s visits for the purpose oftesting sections of drainage, and the results of such tests.

10 Electrical and HeatingInspectors

The Clerk of Works should establish early liaison withthe Electrical and Heating Inspectors so that the worksof the relevant subcontractors are properly co-ordinatedwith the rest of the work on the contract, and all points ofdetail made clear to all concerned. Similar action shouldbe taken, of course, for all other specialist services.

11 Factory Inspector It is the duty of the Clerk of Works to report upon any plant orscaffolding in use, or intended to be used, which appears tobe defective or dangerous. The report should be made to theSites Manager’s office so that the department’s Chief SafetyOfficer may take the appropriate action. The Clerk of Works isalso to note, in the Weekly Report, when a Factory Inspectorvisits the site, and any remarks made on safety matters.

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12 Officers of the ParksDepartment

Good liaison with the appropriate officer of the ParksDepartment should be established during the progress ofthe contract so that arrangements may be made for thecompletion of the planting work, as near as possible tocoincide with the contract completion; and so that theParks Department’s Clerk of Works specialist skills areused to the full in assisting the Site Clerk of Works inobtaining a job that is first class in every way.

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25 Clerks of Works Conditionsof Service and GeneralAdministration

(These notes are intended as a guide to some of the more important of the Conditions ofService of a Clerk of Works. Engagements are subject to the Council’s standing orders,regulations and rules in force from time to time; requests for advice on queries ordifficulties should be made to the Establishment Officer.)

1 Hours of Work The Clerk of Works is required to work the hours of theContractor which, in the building industry at the moment, are39 per week. This requirement is subject to the operation ofthe Clerk of Works Option Absence Scheme, whereunder aClerk of Works must work, where possible, a week of 40hours in order to qualify for the extra leave, i.e.

8 a.m.–12.00 noon12.30 p.m.–4.30 p.m.

Punctual attendance in the morning is essential.

2 Overtime

3 Overtime Claims

Most contractors, except those engaged on maintenancework, do regular overtime.Where the work being done during the overtime periodcannot be properly inspected on the following day, the Clerkof Works will be required to work overtime, i.e. operationssuch as structural concrete work, removal of obstructionsetc. The Clerk of Works will decide when the nature of thework makes it necessary to work overtime.Overtime, because of the operation of the Clerk of WorksOption Absence Scheme, commences after 41 hours havebeen worked in the 5-day week, subject to item 1.If work is carried out on a Saturday on a site with a five-dayweek, a Clerk of Works’ overtime will start from thebeginning of the day’s work, i.e. 8.00 a.m.

Overtime claims must be:1 Submitted to the divisional administration on the first

day of each month for overtime worked in theprevious month showing details of overtime and weeklysub-totals of hours worked and

2 Endorsed ’Operatives on site worked similarovertime’.and signed by the Clerk of Works.

It should be noted that overtime spent on clerical workwhen operatives are not on site does not rank forpayment.All overtime hours which rank for payment should, ofcourse, be shown on the weekly report as well as on theOvertime Claim.

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4 Attendance Records

5 TemporarySheets

Absence

6 Travel Expenses—Home to Site

7 Incremental Scales

8 Established Positions

All Clerks of Works are to show their times of arrival anddeparture and their overtime hours on the Weekly Reportform.Additionally all Clerks of Works are to complete, andhave in County Hall by 3 p.m. every Monday, a timeanalysis sheet AR 74A which sheets will be analysed by theCounty Hall computer for cost of production information.To fill in this form each Clerk of Works will need to know:1 the personal salary code number2 the personal salary classification3 the week number4 the job computer reference number.Each Clerk of Works is given an explanatory sheet as tohow this time analysis sheet AR 74A for computer use is tobe filled in.

Clerks of Works are to leave a note whenever they haveto leave their base sites during working hours, statingdestination, purpose of visit, time of leaving and time ofreturning to the site.The approval of the architect-in-charge must be obtainedbefore leaving the site.

Clerks of Works are in most cases eligible for thereimbursement of a proportion of their travel expensesbetween their home and their site. As an example, taking thecase of a Clerk of Works living and working inside GreaterLondon, travelling expenses between home and site, return,in excess of 21p per day are reimbursed.

Within the incremental scales normal annual incrementswill be paid subject to a certificate by the head of thedivision that the conduct, work and general efficiency ofthe officer has been in all respects satisfactory. Individualswill not normally be advised of annual increments, norwill they necessarily be called for interview at the time anincrement is due. If the head of a division considers,however, that a normal annual increase should bewithheld a written report will be made on the reasons forthis and shown to the officer concerned, who shouldinitial as having seen it.

With very few exceptions Clerks of Works are firstrecruited as temporary Clerks of Works, and subject toadequate reports and medical examination, they arethen moved on to the permanent establishment sometwelve to eighteen months later.Only very occasionally are Clerks of Works engaged onthe basis of individual projects, except for the ’Paintingand Cleaning’ Clerks of Works engaged seasonally.

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9 Superannuation A superannuation contribution of 6% of salary for theGLC Pension Scheme is deducted from a Clerk ofWorks salary from the date of his first joining the Councilas a temporary officer, unless his age is a bar.

10 Place of Employment A Clerk of Works has to be prepared to work anywhere in theGreater London Area. Regard is however paid to where s/helives as far as practicable.When asked to work at some distance outside the GreaterLondon area, the Clerk of Works becomes eligible forsubsistence allowance if the posting is for a limited duration,or special arrangements are explored.

11 Training

12 Car Allowances

13 Leave

14 Leave on building Leave on building operatives’ holidays is now covered by theoperatives’ holidays operation of the Clerk of Works Option Leave Agreement.

Where a Clerk of Works is in need of training, regardis paid to this in posting as far as it is possible to givethe Clerk of Works adequate training by experience.Clerks of Works are regularly sent on courses, and studyfor appropriate qualifications is encouraged. Day releaseis possible for suitable Clerks of Works.

When a Clerk of Works has to be mobile between contractsor in estate areas when public transport is inappropriate, a carallowance may be made available.At the moment this is usually 26.07p per mile for the first3000 miles a year, reducing to 19.87p per mile for the next4000 miles a year, and 15.87p per mile over 7000 miles.Special application has to be made by the Clerk of Works for acar allowance and this is only granted where it is specificallyin the Council’s interest to do so.

The leave year is from 1 April-31 March.Annual entitlement for all Clerks of Works (Grades 1 to4) is:

26 basic working days.

15 Additional leave forlong service

With effect from April 1974 Clerks of Works are entitledto leave additional to the annual leave prescribed for

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16 Special Leave

their grades, based on length of service as follows:After 10 years service—additional 1 dayAfter 15 years service—additional 2 daysAfter 20 years service—additional 3 daysAfter 25 years service—additional 4 daysAfter 30 years service—additional 5 days

There are provisions for petty leave, or special leave inappropriate circumstances, e.g., moving house, funeral of anear relative, or similar urgent private affairs. This is subject toapplication to the Establishment Officer, and should not beregarded as a right.

17 Application for Leave When a Clerk of Works is granted leave it will normally benecessary for the contract to be covered by another Clerk ofWorks. For this reason it is necessary that a Clerk of Worksmakes leave application at least two clear weeks before leaveis required. Longer notice is advisable.

18 Termination of Engagement

19 Illness

20 Accidents

21 Sick Pay

The engagement for an officer on salaried staff may beterminated by one calendar month’s notice in writingon either side; or on the part of the Council by1 Six weeks notice if the employee has ten years but

less than fifteen years continuous service; or2 Eight weeks notice if the employee has fifteen years

or more continuous service.

If an officer is prevented by illness from attending for dutys/he must on the first day of absence notify the fact, givingthe reason, and expected length of absence to theSuperintendent of Works. If the illness continues beyondthree days, the officer must notify the Superintendent ofWorks on the fourth day stating the expected length ofabsence. If the illness lasts for more than 3 working days butless than 8 days (including week-end) Form SC1 should beobtained from doctor’s surgery or hospital, completed, andforwarded to the Establishment Officer. If the absencecontinues beyond 7 days (including week-end) Form SC1should be completed in respect of the first 7 days andfollowed by NHS certificates issued by the GP or hospital. Anofficer must state on the final certificate the intended date forreturn to duty.

Accidents to an officer on duty, however trivial they mayappear at first, should be reported immediately, and anaccident report (CSF40) should be completed and forwardedto the departmental Safety Advisor.

Provided that the requirements as regards notificationof illness and submission of medical certificates are

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complied with and subject to the Council’s right todetermine the contract of service at any time, the follow-ing scales of sick pay are allowed:

Year of Service

In first 4 monthsIn first year thereafterIn Second yearIn Third yearIn Fourth yearIn Fifth yearAfter completing

six years’ service

The scales for sick pay

Full Pay—followed by—Half Pay

1 month Nil1 month 2 months2 months 2 months4 months 4 months5 months 5 months5 months 5 months

6 months 6 months

22 Assessment Boards Assessment boards are held departmentally at intervals.At these boards the Clerk of Works will usually be asked todescribe in some detail the work engaged upon, and will alsobe given the opportunity to ask any questions affecting workor his/her career that may arise.

23 Loss of Council money or property

1 All losses of money or property of the Council,irrespective of the amounts or value are to be reportedimmediately to the Department. Losses include thefts,burglaries and deficiencies discovered on inventorychecks.The report (3 copies) should contain the followinginformation:(a) Date and time of loss and its discovery.(b) Cause of the loss and the circumstances of its

discovery.(c) Value of the individual items concerned. Where

the total value of the losses discovered on anyparticular inventory check total £25 or less and adetailed valuation would involve much work, alist of items and a statement that the total valueof the items was £25 or under will be sufficient.

(d) Contractor’s security arrangements.(e) Whether the loss has been reported to the police.

2 The Department should also be informed of therecovery of any money or property reported lost.

3 In addition, any burglary on a site should be reportedto the police immediately and the contractor asked tocarry out works necessary to make the premisessecure, without prior reference to head office.

4 Safeguarding of council property—cash, stamps, etc.,should never be left in an exposed position in anunoccupied room, or hut, but should be locked away.

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24 Personal property

Claims for the loss or damage of personal propertyshould be addressed to the contractor and not form partof the claim made by the Council for the loss of Councilproperty.

25 Change of Address The Clerk of Works is to notify the department at onceof any change of private address, or of telephonenumber.

26 Correspondence

27 Postage

All communications for the department are to be addressedto The Architect, Greater London Council, The CountyHall, London, SE1. Separate communications are to bemade with respect to each contract supervised but are asfar as possible to be dispatched in one envelope. Theappropriate divisional reference, followed by the Job No.,should be written on the top left hand corner of theenvelope as well as on the documents themselves.On pressing matters the Clerk of Works shouldcommunicate with the department by telephone. Wherecall fees are incurred they are to be charged to pettycash.Correspondence from departments will normally beaddressed to the Clerk of Works and the Clerk of Worksshould inform the department of the full postal address of thesite office as soon as it has been established, and histelephone number.Weekly Reports and Labour Returns are to be posted to reachthe department not later than 3.00 p.m. on the Monday ofeach week.

Requisitions for postage stamps should be made on FormAR.58. An account of requisitions should be kept;postage stamps are not to be charged to petty cash. Anyunused stamps are to be returned to the Departmentwhen no longer required.

28 Visitors to the works Persons other than officers of the department, or thecontractor or his accredited agents, visiting the worksand asking to be furnished with information or to seedrawings, should be required to produce authorisationfrom the architect-in-charge before any such request isgranted, or obtain authorisation from the architect-in-charge by telephone.

29 Photographs Applicants for permission to take photographs on theworks should be referred by telephone to the architect-in-charge.

30 Trade Union visitors

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Personal or written applications to visit the site made byTrade Union officials should be referred to thecontractor’s Site Agent.

31 Enquiries for housing Any enquirers for housing accommodation are to beinformed that all communications regarding lettings onthe Council’s estates should be addressed to the Directorof Housing, either at The County Hall or at the nearestDistrict Office.The names of individual members of the staff must not begiven to such enquirers.

32 Visits from the Press

33 Examination of materials in preparation off-site

In the case of Press visitors, the Clerk of Works is toremember that no communication of any information towhich access is obtained in the course of official dutiesIS to be made to any newspaper, or person.Visitors from a newspaper should be referred to the PressOfficer (of whom they will be aware) at County Hall;and the architect-in-charge should be informed, bytelephone, of the visit.

The Clerk of Works may from time to time need to visitoutside workshops or yards where materials are inpreparation, and satisfy himself as to the quality of materialand the workmanship during execution before the finishedwork is delivered to the site. Prior permission for such visits isto be obtained from the architect-in-charge and theSuperintendent of Works.With the above exceptions the Clerk of Works is notpermitted to visit manufacturers’ works or showroomsduring site working hours.

34 Rules for visits by the When Clerks of Works visit workshops on inspectionClerk of Works to duties the party should consist of never less than a teamWorkshops of two officers. They should proceed in either Council,

public or their own transport, and meals or similar fullrefreshments are to be taken under the officers ownarrangements only.Arrangements should be made for the visiting officers toarrive at the works early in the day, normally not later than9 a.m., and leave only when a satisfactory day’s inspectionhas been carried out. The Sites Manager’s office will arrangetransport when required and the site Clerk of Works shouldnotify that office when visits to workshops are required.

35 Issues A Clerk of Works is issued with the following on entering theservice:

Donkey jacketRubber bootsStockingsMax. and Min. ThermometerRubber torch30 metre Steel Tape—Metric2 metre folding rod—Metric

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36 Use of official position

37 Gifts

together with the permanent issue sets of technicalinformation for Clerks of Works detailed in section’TRAINING AND SUPPLY OF TECHNICALINFORMATION TO CLERKS OF WORKS’.

Application for any of these articles should be made tothe Site Manager’s office.

All departmental documents, plans, photographs, etc.,are to be regarded as classified and are not to go out ofthe department, or to be used for other than officialpurposes without special permission.No official is entitled to have access to any paper which is notrequired in connection with official duties.

The acceptance of gifts from contractors, or sub-contractors, or any of their employees is expresslyforbidden.It is quite common for gifts to be offered at Christmas timeand should these be delivered to an officer in such a way thatthere is no opportunity to refuse or return them, the officershould send or take the gifts to the Establishment Officerwho will arrange for them to be either delivered to one of theLondon hospitals or otherwise disposed of.

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